写成这样,你应该明白了吧?select m.* from scott.emp m (select deptno , avg(sal) sal_avg from scott.emp group by deptno) n where m.deptno = n.deptno and m.sal > n.sal_avg
我想知道select avg(sal) from scott.emp where deptno=e.deptno是不是将不同的各个部门的平均工资都返回?select * from scott.emp e where e.sal > (select avg(sal) from scott.emp where deptno=e.deptno); 还有整个语句的执行有没有什么先后顺序的?
我想知道select avg(sal) from scott.emp where deptno=e.deptno是不是将不同的各个部门的平均工资都返回?改成select avg(sal) from scott.emp group by deptno
select avg(sal),deptno from scott.emp group by deptno
(select deptno , avg(sal) sal_avg from scott.emp group by deptno) n
where m.deptno = n.deptno and m.sal > n.sal_avg
还有整个语句的执行有没有什么先后顺序的?