有个表A表,B表,然后两个表都只有key 和value两个字段.
然后判断A表和B表的的key如果相同的话,把A表的value修改成为B的value
再问下cash when...then...else..end中可以嵌套几个else??
然后判断A表和B表的的key如果相同的话,把A表的value修改成为B的value
再问下cash when...then...else..end中可以嵌套几个else??
调试欢乐多
set value = (select value from b
where b.key = a.key)
where exists (select 1 from b
where b.key = a.key)
merge into a using b on(a.key=b.key)
when matched then update set a.value=b.valueupdate a set a.value=(select value from b where a.key=key)
case when...then...else..end中可以嵌套几个else?
一个
晕!!!