SQL in, not in, exists, not exists

网上很多人在讨论In和Exists的性能对比，本人也搞不懂哪个性能更佳，只是一般在小表中用In，而在大表中用Exists。下面只是举例如果使用，以勉被喷了。

1、In。

select * from table1 a
where a.Id in (select Id from table2)

select * from table1 a
where a.Id not in (select Id from table2)

2、Exists。

select * from QVS_CUSTPACKINGSLIPPRINTJOUR a
where exists 
(select PRINTID from QVS_CustPackingSlipPrintTrans b 
where a.PRINTID = b.PRINTID and b.DATAAREAID in ('QCN'))
and a.DATAAREAID in ('QCN')

select * from QVS_CUSTPACKINGSLIPPRINTJOUR a
where not exists 
(select PRINTID from QVS_CustPackingSlipPrintTrans b 
where a.PRINTID = b.PRINTID and b.DATAAREAID in ('QCN'))
and a.DATAAREAID in ('QCN')