下面有两个T-SQL,乍看之下以为是等效的，实际却不是这样

                         SELECT orderid1 ,
                                LocalCost ,
                                supplyGoodsName ,
                                buyersgoodsid ,
                                JSitId ,
                                GSitId
                         FROM   csc_result WITH ( NOLOCK )
                         WHERE  [level] > 0
                                AND orderid1 LIKE '618464266%'
                                AND ( supplygoodsid NOT IN ( 1085317, 1112957 ) )

                         SELECT     orderid1,
                                    LocalCost ,
                                    supplyGoodsName ,
                                    buyersgoodsid ,
                                    JSitId ,
                                    GSitId
                          FROM      csc_result WITH ( NOLOCK )
                          WHERE     [level] > 0
                                    AND orderid1 LIKE '618464266%'
                                    AND (supplygoodsid  NOT IN ( 1085317,
                                                              1112957 )
                                                              OR SupplyGoodsId IS NULL)

可见not in并不能把null值排除在外