如:select * from t_vpn_list a
where rq='200610'
and status=1
and exists (
select * from bill.t_val_id b
where b.latn=a
and a.val_id=b.val_id
and b.status<>0)exists的意思,我不明确,是判断真假?如何比较?
where rq='200610'
and status=1
and exists (
select * from bill.t_val_id b
where b.latn=a
and a.val_id=b.val_id
and b.status<>0)exists的意思,我不明确,是判断真假?如何比较?
解决方案 »
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