Union two complex queries 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> create table departments
  2  ( deptno NUMBER(2)     constraint D_PK
  3                         primary key
  4  , dname  VARCHAR2(10)
  5  , location VARCHAR2(8)
  6  , mgr    NUMBER(4)
  7  ) ;

Table created.

SQL>
SQL> insert into departments values (10,'ACCOUNTING','NEW YORK',7);

1 row created.

SQL> insert into departments values (20,'TRAINING',  'DALLAS',  4);

1 row created.

SQL> insert into departments values (30,'SALES',     'CHICAGO', 6);

1 row created.

SQL> insert into departments values (40,'HR',        'BOSTON',  9);

1 row created.

SQL>
SQL> select   d.deptno
  2  ,        d.dname
  3  ,        count(e.empno) as headcount
  4  from     emp e
  5  ,        departments d
  6  where    e.deptno = d.deptno
  7  group by d.deptno
  8  ,        d.dname
  9  union
 10  select   x.deptno
 11  ,        x.dname
 12  ,        0        as headcount
 13  from     departments x
 14  where    x.deptno not in (select y.deptno
 15                            from   emp y);

    DEPTNO DNAME       HEADCOUNT
---------- ---------- ----------
        10 ACCOUNTING          3
        20 TRAINING            5
        30 SALES               6
        40 HR                  0

SQL>
SQL>
SQL> drop table emp;

Table dropped.

SQL> drop table departments;

Table dropped.

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Union two complex queries and subquery : UNION « Result Set « Oracle PL / SQL

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