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