在数据库中，以下sql语句执行错误的是a A select deptno,avg(sal) from emp group by deptno where avg(sal)>2000; B select ename,sal A from emp where comm is null order by A desc; C select * from emp where ename like '%\_%' escape '\'; D select * from emp where (job='MANAGER' or job='ANALYST') and sal >2500; E select count(*) from emp where 1=1;