查询,返回空结果集和NULL结果的困惑。
2条查询语句:
1."SELECT CargoId FROM vw_outgo_detail WHERE (OGDate BETWEEN '2013-12-12 0:00:00' AND '2013-12-12 23:59:59') AND CargoId='211404'"
返回空结果集——没有记录。
2."SELECT CargoId,SUM(Quantity) AS sumQuantity,SUM(Amount) AS sumAmount FROM vw_outgo_detail WHERE (OGDate BETWEEN '2013-12-12 0:00:00' AND '2013-12-12 23:59:59') AND CargoId='211404'"
返回一条记录,CargoId,sumQuantity,sumAmount,三个字段都为NULL
问,
1.为什么同样的WHERE子句,结果集却不同?
2.如何修改让第2条语句也返回空结果集。