试题详情
- 单项选择题查询出EMP表中COMM字段为空的记录（）
A、select * from emp where comm='';
B、select * from emp where comm=null;
C、select * from emp where nvl(comm)=0;
D、select * from emp where comm is null;
E、select * from emp where nvl(comm,0)=0;
- D
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A、select * from emp where comm='';
B、select * from emp where comm=null;
C、select * from emp where nvl(comm)=0;
D、select * from emp where comm is null;
E、select * from emp where nvl(comm,0)=0;
关注下方微信公众号，在线模考后查看