零基础带你学习MySQL—字符串相关的函数（十三）

川长思鸟来 2022-10-11 00:59 171阅读 0赞

## 零基础带你学习MySQL—字符串相关的函数（十三） ##

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## 一、`CHARSET (str)`返回子串字符集 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzQ2Mzc0OTY5_size_16_color_FFFFFF_t_70 1]

## 二、`CONCAT`连接子串，将多个列拼接成一列 ##

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## 三、`INSTR(string,substring)`返回`substring`在`string`中出现的位置 ##

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## 四、`UCASE(string2)` 转换成大写 ##

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## 五、`LCASE(string2)` 转换成小写 ##

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## 六、`LEFT(string2,length)`表示从`string2`中的左边取`length`个字符 ##

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## 七、`RIGHT(string2,length)`表示从`string2`中的右边取`length`个字符 ##

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## 八、`LENGTH(string) string`长度\[按照字节\] ##

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## 九、`REPLACE (str,search_str,replace_str)` ##

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## 十、`STRCMP(string1,string2)`逐字比较两字串大小 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzQ2Mzc0OTY5_size_16_color_FFFFFF_t_70 10]

## 十一、`SUBSTRING(str,poisition,length)`从`str`的`position`开始【从1开始计算】，取length个字符 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzQ2Mzc0OTY5_size_16_color_FFFFFF_t_70 11]

## 十二、`LTRIM(string2)`去除前端空格 ##

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## 十三、`RTRIM(string2)`去除后端空格 ##

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## 十四、`TRIM(string)`去除前后端空格 ##

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## 十六、练习 ##

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