Oracle PL/SQL/Select Query/With

With statement and subquery

  
SQL>
SQL> create table emp
  2  ( empno      NUMBER(4)    constraint E_PK primary key
  3  , ename      VARCHAR2(8)
  4  , init       VARCHAR2(5)
  5  , job        VARCHAR2(8)
  6  , mgr        NUMBER(4)
  7  , bdate      DATE
  8  , sal       NUMBER(6,2)
  9  , comm       NUMBER(6,2)
 10  , deptno     NUMBER(2)    default 10
 11  ) ;
Table created.
SQL> insert into emp values(1,"Tom","N",   "TRAINER", 13,date "1965-12-17",  800 , NULL,  20);
1 row created.
SQL> insert into emp values(2,"Jack","JAM", "Tester",6,date "1961-02-20",  1600, 300,   30);
1 row created.
SQL> insert into emp values(3,"Wil","TF" ,  "Tester",6,date "1962-02-22",  1250, 500,   30);
1 row created.
SQL> insert into emp values(4,"Jane","JM",  "Designer", 9,date "1967-04-02",  2975, NULL,  20);
1 row created.
SQL> insert into emp values(5,"Mary","P",  "Tester",6,date "1956-09-28",  1250, 1400,  30);
1 row created.
SQL> insert into emp values(6,"Black","R",   "Designer", 9,date "1963-11-01",  2850, NULL,  30);
1 row created.
SQL> insert into emp values(7,"Chris","AB",  "Designer", 9,date "1965-06-09",  2450, NULL,  10);
1 row created.
SQL> insert into emp values(8,"Smart","SCJ", "TRAINER", 4,date "1959-11-26",  3000, NULL,  20);
1 row created.
SQL> insert into emp values(9,"Peter","CC",   "Designer",NULL,date "1952-11-17",  5000, NULL,  10);
1 row created.
SQL> insert into emp values(10,"Take","JJ", "Tester",6,date "1968-09-28",  1500, 0,     30);
1 row created.
SQL> insert into emp values(11,"Ana","AA",  "TRAINER", 8,date "1966-12-30",  1100, NULL,  20);
1 row created.
SQL> insert into emp values(12,"Jane","R",   "Manager",   6,date "1969-12-03",  800 , NULL,  30);
1 row created.
SQL> insert into emp values(13,"Fake","MG",   "TRAINER", 4,date "1959-02-13",  3000, NULL,  20);
1 row created.
SQL> insert into emp values(14,"Mike","TJA","Manager",   7,date "1962-01-23",  1300, NULL,  10);
1 row created.
SQL>
SQL> with g as
  2        (select   x.deptno
  3         ,        avg(x.sal) avg_sal
  4         from     emp x
  5         group by x.deptno)
  6  select e.ename, e.init, e.sal
  7  from   emp e
  8         join      g
  9         using (deptno)
 10  where  e.sal > g.avg_sal;
ENAME    INIT         SAL
-------- ----- ----------
Peter    CC          5000
Jane     JM          2975
Fake     MG          3000
Smart    SCJ         3000
Jack     JAM         1600
Black    R           2850
6 rows selected.
SQL>
SQL>
SQL> drop table emp;
Table dropped.
SQL>

With the simple CASE statement, you can add many more WHEN blocks

  
SQL>
SQL> BEGIN
  2    CASE
  3      WHEN 1 = 2 THEN
  4        dbms_output.put_line("Case [1 = 2]");
  5      WHEN 2 = 2 THEN
  6        dbms_output.put_line("Case [2 = 2]");
  7      ELSE
  8        dbms_output.put_line("No match");
  9    END CASE;
 10  END;
 11  /
Case [2 = 2]
PL/SQL procedure successfully completed.