Question

MYSQL结构：

 ID | USERID | FRIENDID | Type
-------------------------------
 1  |   10   |    20    | Gold
 2  |   20   |    10    | Gold

 3  |   30   |    40    | Silver
 4  |   40   |    30    | Silver

 5  |   50   |    60    | Gold
 6  |   60   |    50    | Gold

 7  |   70   |    80    | Bronze
 8  |   80   |    70    | Bronze

 9  |   90   |   100    | Bronze
10  |  100   |    90    | Bronze

我想要的是GROUP（ID 1＆amp; ID 2）和（ID 5＆amp; ID 6），因为它们是“黄金”类型， NOT GROUP BY TYPE 。

返回结果：

 1. 10 & 20, type:gold. (GROUP)

 3. 30 & 40, type:silver.
 4. 40 & 30, type:silver.

 5. 50 & 60, type:gold. (GROUP)

 7. 70 & 80, type:bronze.
 8. 80 & 70, type:bronze.

 9. 90 & 100, type:bronze.
10. 100 & 90, type:bronze.

如何使用php查询执行此操作？

演示：http://sqlfiddle.com/#!2/13bd3/1

Answer 1

您需要做的是根据类型添加其他分组子句。当它是'黄金'时，你得到一个常数。否则，您使用id：

select least(userid, friendid), greatest(userid, friendid), type
from t
group by least(userid, friendid), greatest(userid, friendid),
         (case when type = 'gold' then 0 else id end)

这会重新排列非黄金类型的ID顺序。如果排序很重要，那么SQL会更复杂一些：

select (case when type = 'gold' then least(userid, friendid) else userid end),
       (case when type = 'gold' then greatest(userid, friendid) else friendid end),
       type
from t
group by least(userid, friendid), greatest(userid, friendid),
         (case when type = 'gold' then 0 else id end)

Answer 2

SELECT GROUP_CONCAT(friend_id) , type FROM mytable GROUP BY type

Demo

Answer 3

试试这个：

SELECT id, userid, friendid, type 
FROM (SELECT id, userid, friendid, type, 
             IF(LOWER(type) = 'gold', IF(@lasttype=(@lasttype:=TYPE), @auto, @auto:=@auto+1), @auto:=@auto+1)  indx 
      FROM tablename, (SELECT @auto:=1, @lasttype:=0) a 
      ORDER BY id) a 
GROUP BY indx;

MYSQL GROUP由具有特定列的多个不同值组成

3 个答案: