mysql通过关联修改表中两个字段的值_MySQL

mysql通过关联修改表中两个字段的值

Sql代码

update A set a_field=

(select realname from B where A.extension=B.extension and B.extension <> '')

update A a inner join B b on a.extension=b.extension and a.extension <> ''

set a.extenrealname =b.realname