将一列从一个表复制到另一个表

Question

我很困惑如何使用where将列从一个表复制到另一个表.我写了SQL查询,但它说超出事务锁定时间或查询返回多行.
使用mysql
基本上,
我有:

Table 1:  Results
BuildID  platform_to_insert

Table 2:  build
BuildID correct_platform

update results set results.platform_to_insert 
     = (select correct_platform from  
       build where results.BuildID = build.BuildID)

Answer 1

我不相信你需要一个子查询.

UPDATE results, build
SET    results.platform_to_insert = build.correct_platform
WHERE  results.BuildID = build.BuildID

Answer 2

这里有两个选项:

1. 更新表以用BuildID作主键(以避免重复)

2. 更新子查询只返回一个结果

   UPDATE results SET results.platform_to_insert = (
       SELECT correct_platform
       FROM build
       WHERE results.BuildID=build.BuildID LIMIT 1
   );