mysql 将A表的a字段赋值给B表的b字段
2020-03-06 13:03 话猫 阅读(3126) 评论(0) 编辑 收藏 举报A、B为2个不同的表,将A表的a字段赋值给B表的b字段:
update B set b = (select a from A where A.id = B.id) where B.b is null
update B set b = (select a from A where A.id = B.id) where B.b is null
注:where B.b is null为将B表的b字段为空的值赋值为A表的a字段