django数据字段查询

快来打我* 2022-04-16 00:18 278阅读 0赞

#### 5.2.4 字段查询 ####

相当于sql语句中where子句，它可以为filter、exclude和get方法提供参数。

属性名称__比较运算符=值   #是两个下划线

<table> 
 <thead> 
  <tr> 
   <th>操作符</th> 
   <th>说明</th> 
   <th>示例</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>exact/=</td> 
   <td>精确判等</td> 
   <td>uname = ‘admin’ <br><code>uname__exact = 'admin'</code><br><code>uname__exact = None</code> #uname is null</td> 
  </tr> 
  <tr> 
   <td>iexact</td> 
   <td>不区分大小写判等</td> 
   <td>name__iexact = ‘admin’</td> 
  </tr> 
  <tr> 
   <td>contains</td> 
   <td>模糊查询，等价like ‘%值%’</td> 
   <td>uname__contains = ‘admin’</td> 
  </tr> 
  <tr> 
   <td>contains</td> 
   <td>不区分大小写的模糊查询</td> 
   <td>uname__icontains = ‘Admin’</td> 
  </tr> 
  <tr> 
   <td>startswith</td> 
   <td>以…开头</td> 
   <td>uname__startswith = ‘a’</td> 
  </tr> 
  <tr> 
   <td>istartswith</td> 
   <td>（不区分大小写)以…开头</td> 
   <td>uname__istartswith = ‘a’</td> 
  </tr> 
  <tr> 
   <td>endswith</td> 
   <td>以…结尾</td> 
   <td>uname__endswith = ‘m’</td> 
  </tr> 
  <tr> 
   <td>iendswith</td> 
   <td>（不区分大小写)以…结尾</td> 
   <td>uname__iendswith = ‘m’</td> 
  </tr> 
  <tr> 
   <td>isnull</td> 
   <td>判空(等价 = None)</td> 
   <td><code>uname__isnull = True</code> #等价 uname is null<br><code>unam__isnull</code> = False #等价 uname is not null</td> 
  </tr> 
  <tr> 
   <td>in</td> 
   <td>包含</td> 
   <td>uid__in = [1,2,3] #in后面必须是可迭代对象</td> 
  </tr> 
  <tr> 
   <td>range</td> 
   <td>范围测试（相当between and)</td> 
   <td><code>uid__range = [2,5]</code> #uid &gt;=2 and cid &lt;=5</td> 
  </tr> 
  <tr> 
   <td>gt/gte</td> 
   <td>大于/大于等于</td> 
   <td><code>uid__gt = 2</code></td> 
  </tr> 
  <tr> 
   <td>lt/lte</td> 
   <td>小于/小于等于</td> 
   <td>uid__lte = 2</td> 
  </tr> 
  <tr> 
   <td>regex</td> 
   <td>正则匹配</td> 
   <td>uname__regex= r’^a’</td> 
  </tr> 
  <tr> 
   <td>iregex</td> 
   <td>不区分大小写的正则匹配</td> 
   <td>uname__iregex= r’^a’</td> 
  </tr> 
 </tbody> 
</table>

*  in后面可以跟一个子查询，但要求子查询只能返回一个字段
    
        User.objects.filter(uid__in = (2,3,4))
        User.objects.filter(uid__in = [2,3,4])
        res = User.objects.filter(uid__gt = 1).values('uid')  #查询集中只有一个字段uid
        User.objects.filter(uid__in = res
 *  日期查询
    
     *  year、month、day、week\_day、hour、minute、second
    
        #等价sql: select * from User where year(regtime) = 2018
         User.objects.filter(regtime__year = 2018)