SQL通过分组行

Question

假设我有一个表像这样获得共同的价值观：

| uid | group_id | 
----------------- 
| 1 |  1 | 
| 1 |  2 | 
| 1 |  3 | 
| 1 |  4 | 
| 2 |  1 | 
| 2 |  2 | 
| 2 |  3 | 
| 3 |  1 | 
| 3 |  2 | 
| 3 |  4 | 
... 

我怎样才能得到一组共用的group_ids一些一套uids。

例如，
为UID 1,2：常见的group_ids是1,2,3
为UID 1,2,3：常见的group_ids是1和2

Answer 1

假设每个group_ID是独特每uid，（否则你需要使用distinct）

SELECT group_ID 
FROM tableName 
WHERE uid IN (1,2,3) 
GROUP BY group_ID 
HAVING COUNT(*) = 3 

• SQLFiddle Demo (includes two queries)