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--1
SELECT [MT1] FROM tba where [MT1] not in(SELECT [手机] FROM tbb)--结果673条
--2
SELECT [MT1] FROM tba where [MT1] in(SELECT [手机] FROM tbb)--结果0条
这2个语句查出来的结果之和是不是 应该等于 tba的数据总和
可是事实上tba 有24000条数据 么有重复的
谁能告诉我这是怎么回事
我用的sql2008
--1
SELECT [MT1] FROM tba where [MT1] not in(SELECT isnull([手机],'') FROM tbb)--结果673条
--2
SELECT [MT1] FROM tba where [MT1] in(SELECT isnull([手机],'') FROM tbb)--结果0条
有null時改用 exists
select * from tba where not exists(select 1 from tbb where [手机]=tba.[手机])
or
select * from tba where exists(select 1 from tbb where [手机]=tba.[手机])