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我试图在这里搜索答案,很少有问题与我的问题非常相似,但我仍然无法弄清楚如何在下面进行 GROUP BY。
MYSQL结构:
ID | USERID | FRIENDID 1 | 14 | 65 2 | 65 | 14 3 | 12 | 19 4 | 19 | 12
如何使用 php 查询按 ID 1 和 ID 2 和 ID 3 和 ID 4 分组?
结果:
1. 14 & 65 2. 12 & 19
SELECT LEAST(USERID, FRIENDID) as x, GREATEST(USERID, FRIENDID) as y FROM TableName GROUP BY x, y
SELECT CONCAT(USERID, ' & ', FRIENDID) FROM table