A表字段更新为B表的字段值

T1表 结构

id name school

1 ming1 清华大学

2 ming2 北京大学

3 ming3 复旦大学

T2表 结构

id student school

11 ming1 牛津大学

12 ming3 剑桥大学

T1表的name 和 T2表的 student 值是 1对1 的对应。

需求：这两个字段的值相同时，根据B表的school更新A表的school。

语句：

update t1 set school = (select school from t2 where name=student) where exists (select * from t2 as b where name = b.student);

结果：

T1表 结构

id name school

1 ming1 牛津大学

2 ming2 北京大学

3 ming3 剑桥大学

注意：

条件里不要再加本身要更新的表,

PS:

关联查询语句：

select aii.update_time,pn.public_time,pn.* from t_apply_item_instance aii, t_public_notice pn where pn.apply_item_instance_uuid = aii.uuid and

aii.apply_item_uuid in ('0101','0102','0103','0104','0105','0106','0201','0202','0203','0204','0205','0206') and aii.apply_status = 21

and pn.public_type = 1

更新语句：

update t_public_notice set public_time =

(select aii.update_time from t_apply_item_instance aii where apply_item_instance_uuid = aii.uuid and

aii.apply_item_uuid in ('0101','0102','0103','0104','0105','0106','0201','0202','0203','0204','0205','0206') and aii.apply_status = 21

and public_type = 1 )

where exists

(select t1.* from t_apply_item_instance as t1 where apply_item_instance_uuid = t1.uuid and

t1.apply_item_uuid in ('0101','0102','0103','0104','0105','0106','0201','0202','0203','0204','0205','0206') and t1.apply_status = 21

and public_type = 1)

update的表在后面的条件里面是没有了的