将列值从一个表复制到另一个匹配的ID

Question

我有两张桌子

 t1
        id  |  value
        1   |   -
        2   |   -
 t2
       parent_id  |  p_value
        1         |   254
        2         |   124

我想将列p_value从t2复制到t1，其中parent_id = id

Answer 1

update t1, t2 set t1.value = t2.p_value where t1.id=t2.parent_id

Answer 2

试试这个：

   Update t1, t2 set t1.value = t2.p_value where t1.id = t2.parent_id;

Answer 3

试试这个

update t1 join t2 on t2.parent_id= t1.id set t1.value = t2.p_value