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SQL语句查询是否为空 =null及null

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2016-06-07 17:58:311549browse

SQL语句查询是否为空 =null及null实现代码。

a b c d

980515 精頂企業有限公司 簡家豪 NULL

980514 全欣木業有限公司 NULL 123

980514 迅億科技股份有限公司 簡逢浚 NULL

980515 聖越國際企業有限公司 NULL 111

表结构如上所示,要查询C列为空的记录的SQL语句不是select * from table where c=null; 或者 select * from table where c=''; 而应当是 select * from table where c is null; 相反地要查询不为空的则应当是 select * from talbe where c''; 或者 select * from table where c is not null; 注意:不是not is null哦。

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