單項選擇題

查詢出EMP表中COMM字段為空的記錄（）

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;

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單項選擇題

取出工資在2000到3000元（包括上下限）之間的員工（）

A.select * from emp wher sal in (2000,3000);
B.select * from emp wher sal like (2000,3000);
C.select * from emp wher sal = (2000,3000);
D.select * from emp wher sal between 2000 and 3000;

單項選擇題

查詢出所有名字以’S’開始的員工（）

A.select * from emp where ename in 'S%';
B.select * from emp where ename='S%';
C.select * from emp where ename like 'S%';
D.select * from emp where ename like 'S_';