Question

我有一张桌子：

详情

--------------------------------------------------------
ID    |   PARENT_ID    |    DATA_KEY     |   DATA_VALUE
======================================================== 
1     |      1         |     Guitar      |      4
--------------------------------------------------------
2     |      1         |     Radio       |      2
--------------------------------------------------------
3     |      1         |     Tv          |      2
--------------------------------------------------------
4     |      1         |     Drum Kit    |      3
--------------------------------------------------------
5     |      2         |     Guitar      |      4
--------------------------------------------------------
6     |      2         |     Radio       |      2
--------------------------------------------------------
7     |      2         |     Tv          |      2
--------------------------------------------------------
8     |      2         |     Drum Kit    |      3
--------------------------------------------------------
9     |      3         |     Guitar      |      1
--------------------------------------------------------
10    |      3         |     Radio       |      2
--------------------------------------------------------
11    |      3         |     Tv          |      2
--------------------------------------------------------
12    |      3         |     Drum Kit    |      3
--------------------------------------------------------

如何选择满足以下条件的mysql distinct PARENT_ID：

1. DATA_KEY ='吉他'和DATA_VALUE ='4'
1. DATA_KEY ='广播'和 DATA_VALUE ='2'

查询的预期输出应为

-------------
PARENT_ID
=============
  1
-------------
  2
-------------

因为只有PARENT_ID 1和2有'Guitar'='4'和'Radio'='2'

Answer 1

SELECT DISTINCT a.parent_id 
FROM details AS a
JOIN details AS b ON a.parent_id=b.parent_id
WHERE a.data_key='Guitar' AND a.data_value='4' AND
      b.data_key='Radio' AND b.data_value='2';

Answer 2

SELECT DISTINCT Parent_Id
FROM details
WHERE (data_key='Guitar' AND data_value='4') OR
(data_key='Radio' AND data_value='2')

这将获得您请求的结果。

你所评论的尝试很接近，但它使用的是＆＃39; AND＆＃39;而不是＆＃39; OR＆＃39;。

Answer 3

也许你会找这个

   SELECT  a.parent_id 
  FROM details AS a
  JOIN details AS b ON a.parent_id=b.parent_id
  WHERE a.data_key='Guitar' AND a.data_value='4' AND
     b.data_key='Radio' AND b.data_value='2'
  group by a.parent_id ;

demo here

MySQL：选择条件适用于多行的记录

3 个答案: