mysql - TRIM mysql 值在外部查询中不解释为字符串

Question

考虑以下查询

select * from games 
where game_id in 
(
  SELECT TRIM(LEADING ',' FROM 
  ( 
    SELECT games FROM `users_games` WHERE `email`=1656366
  ))
)

第一个内部查询

SELECT TRIM(LEADING ',' FROM 
(
  SELECT games FROM `users_games` WHERE `email`=1656366
))` 

返回7497251,7497252,7497255,7497321,7497326,7497339,7497340,7497364,8178978

但总查询仅返回 game_id = 7497251 行的数据。为什么会这样呢？如果我直接将内部 TRIM 查询的结果提供给外部查询，我会得到所需的结果。谁能解释一下为什么吗？

Answer 1

FIND_IN_SET()应该可以。

select * from games 
where find_in_set(game_id, 
(
  SELECT TRIM(LEADING ',' FROM 
  ( 
    SELECT games FROM `users_games` WHERE `email`=1656366
  ))
)) > 0

但正如@fancyPants所说:

切勿在一列中存储多个值!