A表字段更新為B表的字段值 T1表 結構 id name school 1 ming1 清華大學 2 ming2 北京大學 3 ming3 復旦大學 T2表 結構 id student school 11 ming1 牛津大學 12 ming3 劍橋大學 T1表的name 和 T2表的 student 值是 1對1 的對應。 需求：這兩個字段的值相同時，根據B表的school更新A表的school。 語句： update t1 set school = (select school from t2 where name=student) where exists (select * from t2 as b where name = b.student); 結果： T1表 結構 id name school 1 ming1 牛津大學 2 ming2 北京大學 3 ming3 劍橋大學 注意： 條件裡不要再加本身要更新的表, PS: 關聯查詢語句： 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 更新語句： 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的表在後面的條件裡面是沒有了的
