求教一条ORACLE UPDATE语句的写法假设ORACLE有两个表t1和t2
t1和t2的字段有p_id,user_name请问,怎样根据t1.p_id=t2.p_id,将t2的user_name更新到t1的user_name
t1和t2的字段有p_id,user_name请问,怎样根据t1.p_id=t2.p_id,将t2的user_name更新到t1的user_name
update t1 set user_name=(select user_name from t2 where t1.p_id=p_id and rownum=1)
where exists(select 1 from t2 where t1.p_id=p_id);
要是我就是这样了
update t1 set user_name=(select user_name from t2 where t1.p_id=p_id)
where exists(select 1 from t2 where t1.p_id=p_id);--前几次连这个都没写
MERGE INTO t1
USING t2
ON ( t1.p_id = t2.p_id)
WHEN MATCHED THEN
UPDATE SET
t1.user_name = t2.user_name
MERGE INTO t1 --要更新的表
USING t2 --数据来源表
ON ( t1.p_id = t2.p_id) --根据t1.p_id=t2.p_id
WHEN MATCHED THEN
UPDATE SET
t1.user_name = t2.user_name--将t2的user_name更新到t1的user_name不知道怎么解释,语文不级格人,唉。
update(select t1.user_name t1_name,t2.user_name t2_name from t1,t2 where t1.p_id=t2.p_id)
set t1_name=t2_name