oracle group by having
—max min avg sum count
select max sal min sal from emp
select avg sal sum sal from emp
avg null
select sum comm /count * from emp
count * null
avg sal null null select sum sal /count * from emp
select count * from emp
?count
count sal 0
select max sal from emp
select ename job from emp where sal= select max sal from emp
? 1 select
2 sql
3 select oracle
select avg sal from emp
select * from emp where sal>(select avg(sal) from emp);