做个判断，忘高手指点！
做个if判断，条件是
select sdate from songinfo where datediff(dd,sdate,getdate())> 0
如果条件成立，它执行“update songinfo set dayhit=1”；
不成立的话，执行select * from songinfo ;
SQL语句怎么写？？？
[解决办法]
if exists (select sdate from songinfo where datediff(dd,sdate,getdate())> 0)
update songinfo set dayhit=1
else
select * from songinfo
