mysql 用一个表更新另一个表

转 http://www.cnblogs.com/emanlee/p/4231976.html

1. 更改多列

update student s, city c   set s.city_name = c.name where s.city_code = c.code;

2.使用子查询

update student s set city_name = (select name from city where code = s.city_code);