Mysql從具有條件和限制的另一個表INSERT INTO

Question

我有兩個表有一對多關系table1（一），table2（很多）。

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

現在在table1我需要一個列（ rand_t2_id ）來保存來自table2的id ，我真的不在乎哪一個

這是我試過的查詢

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

如果需要，還需要在某個地方建立限制。 我只需要table2中的一個id

這里沒有運氣，有人知道修復嗎？

Answer 1

IMO你可以試試

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

我假設你的table1上已經有一個名為rand_t2_id的列。

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)

我想那就是你要追求的？

此查詢會將隨機t2_id插入到相關的table1中。