Oracle Aggregate functions

// Aggregate Function
Max, Min, AVG, Count, Sum

Select count (*) from Dept;
Select count (deptno) from Dept;

// User, decode, nvl
Select User from dual;
Select sum (decode (A1, 'abc',), sum (decode (A1, 'bca',) from AA;
Select A1, nvl (A2, 'null') from AA;
Select * from AA where A2 is null;
Select * from AA where A2 is not null;
Select * from AA order by a1 ASC;
Select * from AA order by a1 ASC;
// The query is not repeated.
Select distinct A1 from AA;

Group Query
Select ID, sum (price) from AA group by ID;