mysql - Mysql INSERT INTO 从另一个带有条件和限制的表

Question

我有两个具有一对多关系的表 table1（一个），table2（很多）。

table1 has (t1_id) as KEY
table2 has (t2_id) as KEY and t2_t1_id as as refference to table1

现在table1我需要一个rand_t2_id包含idfrom的列 ( ) table2，我真的不在乎哪一个

这是我试过的查询

INSERT INTO table1 (rand_t2_id)
SELECT t2_id
FROM table2
WHERE table1.t1_id = table2.t2_t1_id;

如果需要，还需要在某处建立限制。我只需要 table2 中的一个 id

运气不好，有人知道解决方法吗？

Answer 1

海事组织你可以试试

UPDATE table1 t1 INNER JOIN table2 t2
  ON t1.t1_id = t2.t2_t1_id;
SET t1.rand_t2_id = t2.t2_id

我假设您rand_t2_id的table1.

Answer 2

INSERT INTO table1 (t2_t1_id, rand_t2_id)
SELECT t2_id
FROM (  SELECT t2_id, t2_t1_id
        FROM table2
        ORDER BY RAND()) AS h
GROUP BY t2_t1_id
ON DUPLICATE KEY UPDATE rand_t2_id = VALUES(rand_t2_id)

我想这就是你所追求的？

此查询会将随机 t2_id 插入相关的 table1。