Hive(十六)--内置函数大全

布满荆棘的人生 2022-06-11 06:39 314阅读 0赞

摘要

Hive内部提供了很多函数给开发者使用，包括数学函数，类型转换函数，条件函数，字符函数，聚合函数，表生成函数等等，这些函数都统称为内置函数。

*  [数学函数][Link 1]
 *  [集合函数][Link 2]
 *  [类型转换函数][Link 3]
 *  [日期函数][Link 4]
 *  [条件函数][Link 5]
 *  [字符函数][Link 6]
 *  [聚合函数][Link 7]
 *  [表生成函数][Link 8]

数学函数

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 Return Type 
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 Name (Signature) 
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 Description 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> round(DOUBLE a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the rounded&nbsp;<code style="margin:0px; padding:0px">BIGINT</code>&nbsp;value of&nbsp;<code style="margin:0px; padding:0px">a</code>. 返回对a四舍五入的BIGINT值 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> round(DOUBLE a, INT d) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;rounded to&nbsp;<code style="margin:0px; padding:0px">d</code>&nbsp;decimal places. 返回DOUBLE型d的保留n位小数的DOUBLW型的近似值 </td> 
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 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> bround(DOUBLE a)</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the rounded BIGINT value of&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;using HALF_EVEN rounding mode (as of&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-11103" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 1.3.0, 2.0.0</a>). Also known as Gaussian rounding or bankers' rounding. Example: bround(2.5) = 2, bround(3.5) = 4. 银行家舍入法（1~4：舍，6~9：进，5-&gt;前位数是偶：舍，5-&gt;前位数是奇：进）</td> 
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 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> bround(DOUBLE a, INT d)</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;rounded to&nbsp;<code style="margin:0px; padding:0px">d</code>&nbsp;decimal places using HALF_EVEN rounding mode (as of&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-11103" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 1.3.0, 2.0.0</a>). Example: bround(8.25, 1) = 8.2, bround(8.35, 1) = 8.4. 银行家舍入法,保留d位小数</td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> BIGINT </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> floor(DOUBLE a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the maximum&nbsp;<code style="margin:0px; padding:0px">BIGINT</code>&nbsp;value that is equal to or less than&nbsp;<code style="margin:0px; padding:0px">a</code> 向下取整，最数轴上最接近要求的值的左边的值 &nbsp;如：6.10-&gt;6 &nbsp; -3.4-&gt;-4 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> BIGINT </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> ceil(DOUBLE a), ceiling(DOUBLE a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the minimum BIGINT value that is equal to or greater than&nbsp;<code style="margin:0px; padding:0px">a</code>. 求其不小于小给定实数的最小整数如：ceil(6) = ceil(6.1)= ceil(6.9) = 6 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> rand(), rand(INT seed) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns a random number (that changes from row to row) that is distributed uniformly from 0 to 1. Specifying the seed will make sure the generated random number sequence is deterministic. 每行返回一个DOUBLE型随机数seed是随机因子 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> exp(DOUBLE a), exp(DECIMAL a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns&nbsp;<code style="margin:0px; padding:0px">ea</code>&nbsp;where&nbsp;<code style="margin:0px; padding:0px">e</code>&nbsp;is the base of the natural logarithm. Decimal version added in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-6327" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.13.0</a>. 返回e的a幂次方， a可为小数 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> ln(DOUBLE a), ln(DECIMAL a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the natural logarithm of the argument&nbsp;<code style="margin:0px; padding:0px">a</code>. Decimal version added in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-6327" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.13.0</a>. 以自然数为底d的对数，a可为小数 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> log10(DOUBLE a), log10(DECIMAL a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the base-10 logarithm of the argument&nbsp;<code style="margin:0px; padding:0px">a</code>. Decimal version added in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-6327" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.13.0</a>. 以10为底d的对数，a可为小数 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> log2(DOUBLE a), log2(DECIMAL a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the base-2 logarithm of the argument&nbsp;<code style="margin:0px; padding:0px">a</code>. Decimal version added in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-6327" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.13.0</a>. 以2为底数d的对数，a可为小数 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> log(DOUBLE base, DOUBLE a) log(DECIMAL base, DECIMAL a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the base-<code style="margin:0px; padding:0px">base</code>&nbsp;logarithm of the argument&nbsp;<code style="margin:0px; padding:0px">a</code>.&nbsp;Decimal versions added in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-6327" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.13.0</a>. 以base为底的对数，base 与 a都是DOUBLE类型 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> pow(DOUBLE a, DOUBLE p), power(DOUBLE a, DOUBLE p) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns&nbsp;<code style="margin:0px; padding:0px">ap</code>. 计算a的p次幂 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> sqrt(DOUBLE a), sqrt(DECIMAL a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the square root of&nbsp;<code style="margin:0px; padding:0px">a</code>. Decimal version added in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-6327" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.13.0</a>. 计算a的平方根 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> STRING </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> bin(BIGINT a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the number in binary format (see&nbsp;<a href="http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_bin" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_bin</a>). 计算二进制a的STRING类型，a为BIGINT类型 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> STRING </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> hex(BIGINT a) hex(STRING a) hex(BINARY a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> If the argument is an&nbsp;<code style="margin:0px; padding:0px">INT</code>&nbsp;or&nbsp;<code style="margin:0px; padding:0px">binary</code>,&nbsp;<code style="margin:0px; padding:0px">hex</code>&nbsp;returns the number as a&nbsp;<code style="margin:0px; padding:0px">STRING</code>&nbsp;in hexadecimal format. Otherwise if the number is a&nbsp;<code style="margin:0px; padding:0px">STRING</code>, it converts each character into its hexadecimal representation and returns the resulting&nbsp;<code style="margin:0px; padding:0px">STRING</code>. (See<a href="http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_hex" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_hex</a>,&nbsp;<code style="margin:0px; padding:0px">BINARY</code>&nbsp;version as of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-2482" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">0.12.0</a>.) 计算十六进制a的STRING类型，如果a为STRING类型就转换成字符相对应的十六进制 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> BINARY </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> unhex(STRING a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Inverse of hex. Interprets each pair of characters as a hexadecimal number and converts to the byte representation of the number. (<code style="margin:0px; padding:0px">BINARY</code>&nbsp;version as of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-2482" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">0.12.0</a>, used to return a string.) hex的逆方法 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> STRING </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> conv(BIGINT num, INT from_base, INT to_base), conv(STRING num, INT from_base, INT to_base) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Converts a number from a given base to another (see&nbsp;<a href="http://dev.mysql.com/doc/refman/5.0/en/mathematical-functions.html#function_conv" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">http://dev.mysql.com/doc/refman/5.0/en/mathematical-functions.html#function_conv</a>). 将GIGINT/STRING类型的num从from_base进制转换成to_base进制 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> abs(DOUBLE a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the absolute value. 计算a的绝对值 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> INT or DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> pmod(INT a, INT b), pmod(DOUBLE a, DOUBLE b) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the positive value of&nbsp;<code style="margin:0px; padding:0px">a mod b</code>. a对b取模 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> sin(DOUBLE a), sin(DECIMAL a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the sine of&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;(<code style="margin:0px; padding:0px">a</code>&nbsp;is in radians). Decimal version added in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-6327" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.13.0</a>. 求a的正弦值 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> asin(DOUBLE a), asin(DECIMAL a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the arc sin of&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;if -1&lt;=a&lt;=1 or NULL otherwise. Decimal version added in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-6327" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.13.0</a>. 求d的反正弦值 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> cos(DOUBLE a), cos(DECIMAL a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the cosine of&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;(<code style="margin:0px; padding:0px">a</code>&nbsp;is in radians). Decimal version added in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-6327" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.13.0</a>. 求余弦值 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> acos(DOUBLE a), acos(DECIMAL a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the arccosine of&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;if -1&lt;=a&lt;=1 or NULL otherwise. Decimal version added in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-6327" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.13.0</a>. 求反余弦值 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> tan(DOUBLE a), tan(DECIMAL a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the tangent of&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;(<code style="margin:0px; padding:0px">a</code>&nbsp;is in radians). Decimal version added in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-6327" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.13.0</a>. 求正切值 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> atan(DOUBLE a), atan(DECIMAL a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the arctangent of&nbsp;<code style="margin:0px; padding:0px">a</code>. Decimal version added in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-6327" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.13.0</a>. 求反正切值 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> degrees(DOUBLE a), degrees(DECIMAL a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Converts value of&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;from radians to degrees. Decimal version added in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-6385" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.13.0</a>. 奖弧度值转换角度值 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> radians(DOUBLE a), radians(DOUBLE a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Converts value of&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;from degrees to radians. Decimal version added in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-6327" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.13.0</a>. 将角度值转换成弧度值 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> INT or DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> positive(INT a), positive(DOUBLE a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns&nbsp;<code style="margin:0px; padding:0px">a</code>. 返回a </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> INT or DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> negative(INT a), negative(DOUBLE a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns&nbsp;<code style="margin:0px; padding:0px">-a</code>. 返回a的相反数 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE or INT </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> sign(DOUBLE a), sign(DECIMAL a) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the sign of&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;as '1.0' (if&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;is positive) or '-1.0' (if&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;is negative), '0.0' otherwise. The decimal version returns INT instead of DOUBLE. Decimal version added in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-6246" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.13.0</a>. 如果a是正数则返回1.0，是负数则返回-1.0，否则返回0.0 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> e() </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the value of&nbsp;<code style="margin:0px; padding:0px">e</code>. 数学常数e </td> 
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 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> pi() </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the value of&nbsp;<code style="margin:0px; padding:0px">pi</code>. 数学常数pi </td> 
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 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> BIGINT</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> factorial(INT a)</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the factorial of&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;(as of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-9857" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">1.2.0</a>). Valid&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;is [0..20]. 求a的阶乘</td> 
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 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> DOUBLE</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> cbrt(DOUBLE a)</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the cube root of&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;double value&nbsp;(as of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-9858" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">1.2.0</a>). 求a的立方根</td> 
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 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> &nbsp; INT BIGINT </td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> shiftleft(TINYINT|SMALLINT|INT a, INT b) shiftleft(BIGINT a, INT&nbsp;b) </td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Bitwise left shift (as of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-9859" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">1.2.0</a>). Shifts&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;<code style="margin:0px; padding:0px">b</code>&nbsp;positions to the left. Returns int for tinyint, smallint and int&nbsp;<code style="margin:0px; padding:0px">a</code>. Returns bigint for bigint&nbsp;<code style="margin:0px; padding:0px">a</code>. 按位左移 </td> 
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 <tr style="margin:0px; padding:0px"> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> INT BIGINT </td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> shiftright(TINYINT|SMALLINT|INT a, INTb) shiftright(BIGINT a, INT&nbsp;b) </td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Bitwise right shift (as of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-9859" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">1.2.0</a>). Shifts&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;<code style="margin:0px; padding:0px">b</code>&nbsp;positions to the right. Returns int for tinyint, smallint and int&nbsp;<code style="margin:0px; padding:0px">a</code>. Returns bigint for bigint&nbsp;<code style="margin:0px; padding:0px">a</code>. 按拉右移 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> INT BIGINT </td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> shiftrightunsigned(TINYINT|SMALLINT|INTa, INT b), shiftrightunsigned(BIGINT a, INT b) </td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Bitwise unsigned right shift (as of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-9859" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">1.2.0</a>).&nbsp;Shifts&nbsp;<code style="margin:0px; padding:0px">a</code>&nbsp;<code style="margin:0px; padding:0px">b</code>&nbsp;positions to the right. Returns int for tinyint, smallint and int&nbsp;<code style="margin:0px; padding:0px">a</code>. Returns bigint for bigint&nbsp;<code style="margin:0px; padding:0px">a</code>. 无符号按位右移（&lt;&lt;&lt;） </td> 
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 <tr style="margin:0px; padding:0px"> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> T</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> greatest(T v1, T v2, ...)</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the greatest value of the list of values (as of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-9402" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">1.1.0</a>). Fixed to return NULL when one or more arguments are NULL, and strict type restriction relaxed, consistent with "&gt;" operator (as of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-12082" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">2.0.0</a>). 求最大值</td> 
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 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> T</td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> least(T v1, T v2, ...)</td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the least value of the list of values (as of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-9402" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">1.1.0</a>).&nbsp;Fixed to return NULL when one or more arguments are NULL, and strict type restriction relaxed, consistent with "&lt;" operator (as of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-12082" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">2.0.0</a>). 求最小值</td> 
 </tr> 
 </tbody> 
</table>

集合函数

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 Return Type 
 </div> </td> 
 <th style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 
 <div style="margin:0px; padding:0px"> 
 Name(Signature) 
 </div> </th> 
 <th style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 
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 Description 
 </div> </th> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> int </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> size(Map&lt;K.V&gt;) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the number of elements in the map type. 求map的长度 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> int </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> size(Array&lt;T&gt;) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the number of elements in the array type. 求数组的长度 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> array&lt;K&gt; </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> map_keys(Map&lt;K.V&gt;) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns an unordered array containing the keys of the input map. 返回map中的所有key </td> 
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 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> array&lt;V&gt; </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> map_values(Map&lt;K.V&gt;) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns an unordered array containing the values of the input map. 返回map中的所有value </td> 
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 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> boolean </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> array_contains(Array&lt;T&gt;, value) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns TRUE if the array contains value. 如该数组Array&lt;T&gt;包含value返回true。，否则返回false </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> array </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> sort_array(Array&lt;T&gt;) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Sorts the input array in ascending order according to the natural ordering of the array elements and returns it (as of version&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-2279" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">0.9.0</a>). 按自然顺序对数组进行排序并返回 </td> 
 </tr> 
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</table>

类型转换函数

日期函数

条件函数

字符函数

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 Return Type 
 </div> </td> 
 <th style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 
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 Name(Signature) 
 </div> </th> 
 <th style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> 
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 Description 
 </div> </th> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> int </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> ascii(string str) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the numeric value of the first &nbsp;character of str. 返回str中首个ASCII字符串的整数值 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> base64(binary bin) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Converts the argument from binary to a base 64 string (as of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-2482" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">0.12.0</a>).. 将二进制bin转换成64位的字符串 </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> concat(string|binary A, string|binary B...) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the string or bytes resulting from concatenating the strings or bytes passed in as parameters in order. For example, concat('foo', 'bar') results in 'foobar'. Note that this function can take any number of input strings.. 对二进制字节码或字符串按次序进行拼接 </td> 
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 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> array&lt;struct&lt;string,double&gt;&gt; </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> context_ngrams(array&lt;array&lt;string&gt;&gt;, array&lt;string&gt;, int K, int pf) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the top-k contextual N-grams from a set of tokenized sentences, given a string of "context". See&nbsp;<a href="https://cwiki.apache.org/confluence/display/Hive/StatisticsAndDataMining" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">StatisticsAndDataMining</a>&nbsp;for more information.. 与ngram类似，但context_ngram()允许你预算指定上下文(数组)来去查找子序列，具体看<a href="https://cwiki.apache.org/confluence/display/Hive/StatisticsAndDataMining" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">StatisticsAndDataMining</a>(这里的解释更易懂) </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> concat_ws(string SEP, string A, string B...) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Like concat() above, but with custom separator SEP.. 与concat()类似，但使用指定的分隔符喜进行分隔 </td> 
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 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> concat_ws(string SEP, array&lt;string&gt;) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Like concat_ws() above, but taking an array of strings. (as of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-2203" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">0.9.0</a>). 拼接Array中的元素并用指定分隔符进行分隔 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> decode(binary bin, string charset) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Decodes the first argument into a String using the provided character set (one of 'US-ASCII', 'ISO-8859-1', 'UTF-8', 'UTF-16BE', 'UTF-16LE', 'UTF-16'). If either argument is null, the result will also be null. (As of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-2482" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">0.12.0</a>.). 使用指定的字符集charset将二进制值bin解码成字符串，支持的字符集有：'US-ASCII', 'ISO-8859-1', 'UTF-8', 'UTF-16BE', 'UTF-16LE', 'UTF-16'，如果任意输入参数为NULL都将返回NULL </td> 
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 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> binary </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> encode(string src, string charset) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Encodes the first argument into a BINARY using the provided character set (one of 'US-ASCII', 'ISO-8859-1', 'UTF-8', 'UTF-16BE', 'UTF-16LE', 'UTF-16'). If either argument is null, the result will also be null. (As of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-2482" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">0.12.0</a>.). 使用指定的字符集charset将字符串编码成二进制值，支持的字符集有：'US-ASCII', 'ISO-8859-1', 'UTF-8', 'UTF-16BE', 'UTF-16LE', 'UTF-16'，如果任一输入参数为NULL都将返回NULL </td> 
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 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> int </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> find_in_set(string str, string strList) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the first occurance of str in strList where strList is a comma-delimited string. Returns null if either argument is null. Returns 0 if the first argument contains any commas. For example, find_in_set('ab', 'abc,b,ab,c,def') returns 3.. 返回以逗号分隔的字符串中str出现的位置，如果参数str为逗号或查找失败将返回0，如果任一参数为NULL将返回NULL回 </td> 
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 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> format_number(number x, int d) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Formats the number X to a format like '#,###,###.##', rounded to D decimal places, and returns the result as a string. If D is 0, the result has no decimal point or fractional part. (As of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-2694" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">0.10.0</a>; bug with float types fixed in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-7257" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.14.0</a>, decimal type support added in&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-7279" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.14.0</a>). 将数值X转换成"#,###,###.##"格式字符串，并保留d位小数，如果d为0，将进行四舍五入且不保留小数 </td> 
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 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> get_json_object(string json_string, string path) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Extracts json object from a json string based on json path specified, and returns json string of the extracted json object. It will return null if the input json string is invalid.&nbsp;NOTE: The json path can only have the characters [0-9a-z_], i.e., no upper-case or special characters. Also, the keys *cannot start with numbers.* This is due to restrictions on Hive column names.. 从指定路径上的JSON字符串抽取出JSON对象，并返回这个对象的JSON格式，如果输入的JSON是非法的将返回NULL,注意此路径上JSON字符串只能由数字 字母 下划线组成且不能有大写字母和特殊字符，且key不能由数字开头，这是由于Hive对列名的限制 </td> 
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 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> boolean </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> in_file(string str, string filename) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns true if the string str appears as an entire line in filename.. 如果文件名为filename的文件中有一行数据与字符串str匹配成功就返回true </td> 
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 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> int </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> instr(string str, string substr) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the position of the first occurrence of&nbsp;<code style="margin:0px; padding:0px">substr</code>&nbsp;in&nbsp;<code style="margin:0px; padding:0px">str</code>. Returns&nbsp;<code style="margin:0px; padding:0px">null</code>&nbsp;if either of the arguments are&nbsp;<code style="margin:0px; padding:0px">null</code>&nbsp;and returns&nbsp;<code style="margin:0px; padding:0px">0</code>&nbsp;if&nbsp;<code style="margin:0px; padding:0px">substr</code>&nbsp;could not be found in&nbsp;<code style="margin:0px; padding:0px">str</code>. Be aware that this is not zero based. The first character in&nbsp;<code style="margin:0px; padding:0px">str</code>&nbsp;has index 1.. 查找字符串str中子字符串substr出现的位置，如果查找失败将返回0，如果任一参数为Null将返回null，注意位置为从1开始的 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> int </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> length(string A) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the length of the string.. 返回字符串的长度 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> int </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> locate(string substr, string str[, int pos]) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the position of the first occurrence of substr in str after position pos.. 查找字符串str中的pos位置后字符串substr第一次出现的位置 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> lower(string A) lcase(string A) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the string resulting from converting all characters of B to lower case. For example, lower('fOoBaR') results in 'foobar'.. 将字符串A的所有字母转换成小写字母 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> lpad(string str, int len, string pad) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns str, left-padded with pad to a length of len.. 从左边开始对字符串str使用字符串pad填充，最终len长度为止，如果字符串str本身长度比len大的话，将去掉多余的部分 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> ltrim(string A) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the string resulting from trimming spaces from the beginning(left hand side) of A. For example, ltrim(' foobar ') results in 'foobar '.. 去掉字符串A前面的空格 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> array&lt;struct&lt;string,double&gt;&gt; </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> ngrams(array&lt;array&lt;string&gt;&gt;, int N, int&nbsp;K, int pf) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the top-k N-grams from a set of tokenized sentences, such as those returned by the sentences() UDAF. See&nbsp;<a href="https://cwiki.apache.org/confluence/display/Hive/StatisticsAndDataMining" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">StatisticsAndDataMining</a>&nbsp;for more information.. 返回出现次数TOP K的的子序列,n表示子序列的长度，具体看<a href="https://cwiki.apache.org/confluence/display/Hive/StatisticsAndDataMining" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">StatisticsAndDataMining</a>&nbsp;(这里的解释更易懂) </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> parse_url(string urlString, string partToExtract [, string keyToExtract]) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the specified part from the URL. Valid values for partToExtract include HOST, PATH, QUERY, REF, PROTOCOL, AUTHORITY, FILE, and USERINFO. For example, parse_url('http://facebook.com/path1/p.php?k1=v1&amp;k2=v2#Ref1', 'HOST') returns 'facebook.com'. Also a value of a particular key in QUERY can be extracted by providing the key as the third argument, for example, parse_url('http://facebook.com/path1/p.php?k1=v1&amp;k2=v2#Ref1', 'QUERY', 'k1') returns 'v1'.. 返回从URL中抽取指定部分的内容，参数url是URL字符串，而参数partToExtract是要抽取的部分，这个参数包含(HOST, PATH, QUERY, REF, PROTOCOL, AUTHORITY, FILE, and USERINFO,例如：parse_url('http://facebook.com/path1/p.php?k1=v1&amp;k2=v2#Ref1', 'HOST') ='facebook.com'，如果参数partToExtract值为QUERY则必须指定第三个参数key &nbsp;如：parse_url('http://facebook.com/path1/p.php?k1=v1&amp;k2=v2#Ref1', 'QUERY', 'k1') =‘v1’ </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> printf(String format, Obj... args) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the input formatted according do printf-style format strings (as of Hive<a href="https://issues.apache.org/jira/browse/HIVE-2695" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">0.9.0</a>).. 按照printf风格格式输出字符串 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> regexp_extract(string subject, string pattern, int index) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the string extracted using the pattern. For example, regexp_extract('foothebar', 'foo(.*?)(bar)', 2) returns 'bar.' Note that some care is necessary in using predefined character classes: using '\s' as the second argument will match the letter s; '\\s' is necessary to match whitespace, etc. The 'index' parameter is the Java regex Matcher group() method index. See docs/api/java/util/regex/Matcher.html for more information on the 'index' or Java regex group() method.. 抽取字符串subject中符合正则表达式pattern的第index个部分的子字符串，注意些预定义字符的使用，如第二个参数如果使用'\s'将被匹配到s,'\\s'才是匹配空格 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> regexp_replace(string INITIAL_STRING, string PATTERN, string REPLACEMENT) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the string resulting from replacing all substrings in INITIAL_STRING that match the java regular expression syntax defined in PATTERN with instances of REPLACEMENT. For example, regexp_replace("foobar", "oo|ar", "") returns 'fb.' Note that some care is necessary in using predefined character classes: using '\s' as the second argument will match the letter s; '\\s' is necessary to match whitespace, etc.. 按照Java正则表达式PATTERN将字符串INTIAL_STRING中符合条件的部分成REPLACEMENT所指定的字符串，如里REPLACEMENT这空的话，抽符合正则的部分将被去掉 &nbsp;如：regexp_replace("foobar", "oo|ar", "") = 'fb.'&nbsp;注意些预定义字符的使用，如第二个参数如果使用'\s'将被匹配到s,'\\s'才是匹配空格 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> repeat(string str, int n) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Repeats str n times.. 重复输出n次字符串str </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> reverse(string A) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the reversed string.. 反转字符串 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> rpad(string str, int len, string pad) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns str, right-padded with pad to a length of len.. 从右边开始对字符串str使用字符串pad填充，最终len长度为止，如果字符串str本身长度比len大的话，将去掉多余的部分 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> rtrim(string A) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the string resulting from trimming spaces from the end(right hand side) of A. For example, rtrim(' foobar ') results in ' foobar'.. 去掉字符串后面出现的空格 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> array&lt;array&lt;string&gt;&gt; </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> sentences(string str, string lang, string locale) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Tokenizes a string of natural language text into words and sentences, where each sentence is broken at the appropriate sentence boundary and returned as an array of words. The 'lang' and 'locale' are optional arguments. For example, sentences('Hello there! How are you?') returns ( ("Hello", "there"), ("How", "are", "you") ).. 字符串str将被转换成单词数组，如：sentences('Hello there! How are you?') =( ("Hello", "there"), ("How", "are", "you") ) </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> space(int n) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns a string of n spaces.. 返回n个空格 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> array </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> split(string str, string pat) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Splits str around pat (pat is a regular expression).. 按照正则表达式pat来分割字符串str,并将分割后的数组字符串的形式返回 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> map&lt;string,string&gt; </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> str_to_map(text[, delimiter1, delimiter2]) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Splits text into key-value pairs using two delimiters. Delimiter1 separates text into K-V pairs, and Delimiter2 splits each K-V pair. Default delimiters are ',' for delimiter1 and '=' for delimiter2.. 将字符串str按照指定分隔符转换成Map，第一个参数是需要转换字符串，第二个参数是键值对之间的分隔符，默认为逗号;第三个参数是键值之间的分隔符，默认为"=" </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> substr(string|binary A, int start) substring(string|binary A, int start) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the substring or slice of the byte array of A starting from start position till the end of string A. For example, substr('foobar', 4) results in 'bar' (see [<a href="http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_substr" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_substr</a>]).. 对于字符串A,从start位置开始截取字符串并返回 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> substr(string|binary A, int start, int len) substring(string|binary A, int start, int len) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the substring or slice of the byte array of A starting from start position with length len. For example, substr('foobar', 4, 1) results in 'b' (see [<a href="http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_substr" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">http://dev.mysql.com/doc/refman/5.0/en/string-functions.html#function_substr</a>]).. 对于二进制/字符串A,从start位置开始截取长度为length的字符串并返回 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> substring_index(string A, string delim, int count)</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the substring from string A before count occurrences of the delimiter delim (as of&nbsp;Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-686" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">1.3.0</a>). If count is positive, everything to the left of the final delimiter (counting from the left) is returned. If count is negative, everything to the right of the final delimiter (counting from the right) is returned. Substring_index performs a case-sensitive match when searching for delim. Example: substring_index('www.apache.org', '.', 2) = 'www.apache'.. 截取第count分隔符之前的字符串，如count为正则从左边开始截取，如果为负则从右边开始截取 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> translate(string|char|varchar input, string|char|varchar from, string|char|varchar to) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Translates the input string by replacing the characters present in the&nbsp;<code style="margin:0px; padding:0px">from</code>&nbsp;string with the corresponding characters in the&nbsp;<code style="margin:0px; padding:0px">to</code>&nbsp;string. This is similar to the&nbsp;<code style="margin:0px; padding:0px">translate</code>function in&nbsp;<a href="http://www.postgresql.org/docs/9.1/interactive/functions-string.html" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">PostgreSQL</a>. If any of the parameters to this UDF are NULL, the result is NULL as well. (Available as of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-2418" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">0.10.0</a>, for string types) Char/varchar support added as of&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-6622" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">Hive 0.14.0</a>.. 将input出现在from中的字符串替换成to中的字符串 如：translate("MOBIN","BIN","M")="MOM" </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> trim(string A) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the string resulting from trimming spaces from both ends of A. For example, trim(' foobar ') results in 'foobar'. 将字符串A前后出现的空格去掉 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> binary </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> unbase64(string str) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Converts the argument from a base 64 string to BINARY. (As of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-2482" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">0.12.0</a>.). 将64位的字符串转换二进制值 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> upper(string A) ucase(string A) </td> 
 <td style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the string resulting from converting all characters of A to upper case. For example, upper('fOoBaR') results in 'FOOBAR'.. 将字符串A中的字母转换成大写字母 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> initcap(string A)</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns string, with the first letter of each word in uppercase, all other letters in lowercase. Words are delimited by whitespace.&nbsp;(As of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-3405" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">1.1.0</a>.). 将字符串A转换第一个字母大写其余字母的字符串 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> int</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> levenshtein(string A, string B)</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns the Levenshtein distance between two strings&nbsp;(as of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-9556" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">1.2.0</a>). For example, levenshtein('kitten', 'sitting') results in 3.. 计算两个字符串之间的差异大小 &nbsp;如：levenshtein('kitten', 'sitting') = 3 </td> 
 </tr> 
 <tr style="margin:0px; padding:0px"> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> string</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> soundex(string A)</td> 
 <td colspan="1" style="margin:0px; padding:3px; border:1px solid silver; border-collapse:collapse"> Returns soundex code of the string&nbsp;(as of Hive&nbsp;<a href="https://issues.apache.org/jira/browse/HIVE-9738" style="margin:0px; padding:0px; color:rgb(7,93,179)" rel="nofollow">1.2.0</a>). For example, soundex('Miller') results in M460.. 将普通字符串转换成soundex字符串 </td> 
 </tr> 
 </tbody> 
</table>

聚合函数

表生成函数

![Image 1][]参考资料

# [LanguageManual UDF][] #

《Hive权威指南》

[Link 1]: http://www.cnblogs.com/MOBIN/p/5618747.html#1
[Link 2]: http://www.cnblogs.com/MOBIN/p/5618747.html#2
[Link 3]: http://www.cnblogs.com/MOBIN/p/5618747.html#3
[Link 4]: http://www.cnblogs.com/MOBIN/p/5618747.html#4
[Link 5]: http://www.cnblogs.com/MOBIN/p/5618747.html#5
[Link 6]: http://www.cnblogs.com/MOBIN/p/5618747.html#6
[Link 7]: http://www.cnblogs.com/MOBIN/p/5618747.html#7
[Link 8]: http://www.cnblogs.com/MOBIN/p/5618747.html#8
[Image 1]: 
[LanguageManual UDF]: https://cwiki.apache.org/confluence/display/Hive/LanguageManual+UDF