Set Operators (union, union all, minus, intersect)

Set Operators

Used to Combine output of more than one select statements on following conditions

1) All select statement should have equal number of columns

2) Datatype of each respective column must be same.

1) Union all

2) union

3) minus

4) Intersect

We will perform operation on below two tables

Table 1 emp1

Table 2 emp2

1) Union all

select emp1.empno from emp1;

union all

select emp2.empno from emp2;

4) minus

select emp1.empno from emp1

minus

select emp2.EMPNO from emp2;