Question

我有一个像这样的查询，

SELECT SOME_ID, COUNT(ANOTHER_ID) AS WITHOUT_FILTER 
from SOME_TABLE GROUP BY SOME_ID

这会让我回头

+------------+------------------+
| SOME_ID    | WITHOUT_FILTER   |
+------------+------------------+
|  1         | 40               |
|  2         | 30               |
+------------+------------------+

我有一个相同的查询，条件为我提供过滤值。

SELECT SOME_ID, COUNT(ANOTHER_ID) AS WITH_FILTER 
from SOME_TABLE WHERE SOME_COL > 10 GROUP BY SOME_ID

在groups_by部分

中返回明显较小的值

+------------+----------------+
| SOME_ID    | WITH_FILTER    |
+------------+----------------+
|  1         | 20             |
|  2         | 15             |
+------------+----------------+

现在，我需要一个查询来给我两个计数值，即在一个查询中有条件和无条件。结果应该是这样的

+----------+----------------+---------------+
| SOME_ID  | WITHOUT_FILTER | WITH_FILTER   |
+----------+----------------+---------------+
|  1       | 40             | 20            |
|  2       | 30             | 15            |
+------------+--------------+---------------+

请帮帮我。

Answer 1

你可以这样做：

SELECT 
    SOME_ID, 
    COUNT(ANOTHER_ID) AS WITHOUT_FILTER
    SUM(case when SOME_CONDITION then 1 else 0 end) AS WITH_FILTER

from SOME_TABLE GROUP BY SOME_ID

Answer 2

您可以使用IF（）和SUM获得“COUNT，但仅限于符合条件的行”效果。

 SELECT SOME_ID, 
        COUNT(ANOTHER_ID) AS WITHOUT_FILTER,
        SUM(IF(SOME_COL > 10, 1, 0)) AS WITH_FILTER
 FROM SOME_TABLE GROUP BY SOME_ID

（注意：如果ANOTHER_ID永远为NULL，这个解决方案以及除Adrian之外的所有其他解决方案都有一个微妙的问题。如果是这样的话，那么Adrian是唯一真正正确的问题。）

Answer 3

出于学习目的，这是我的2美分。您可以在两个字段中使用COUNT：

SELECT SOME_ID, 
       COUNT(ANOTHER_ID) AS WITHOUT_FILTER
       COUNT(case 
               when WHEN SOME_COL > 10 then ANOTHER_ID 
               else NULL 
             end) AS WITH_FILTER
from SOME_TABLE GROUP BY SOME_ID

诀窍是COUNT计算非空值。此功能支持ANSI SQL，BTW。

Answer 4

尝试CASE和SUM合并：

SELECT SOME_ID, COUNT(ANOTHER_ID) as WITHOUT_FILTER,
SUM(CASE WHEN SOME_COL > 10 THEN 1 else 0 END) as WITH_FILTER
from SOME_TABLE GROUP BY SOME_ID;

Answer 5

SELECT T1.SOME_ID, 
       COUNT(T1.ANOTHER_ID) AS WITH_FILTER,
       COUNT(T2.ANOTHER_ID) AS WITHOUT_FILTER 
FROM   SOME_TABLE as T1, 
       SOME_TABLE as T2
WHERE 
      T1.SOME_ID=T2.SOME_ID
  AND T2.SOME_COL > 10
GROUP BY T1.SOME_ID, T2.SOME_ID

或者如果您的条件变得过于敏感，您可以使用2个视图合并

需要一个双人组的价值

5 个答案: