SQL - SET OPERATORS

SET operators are special type of operators which are used to combine the result of two queries.

FOUR TYPE SET OPERATORS:
        1. UNION
        2. UNION ALL
        3. INTERSECT
        4. MINUS
1. UNION:
It returns all distinct rows selected by either query 


	Select  * from tesdb01
	Union
	Select  * from tesdb02;
	SQL> select * from tesdb01 union select * from tesdb02;

	COURES_ID             NAME                 COURSE_NAME
	----------    --------------------   --------------------
		  101            arun                 oracle_dba
		  102            babu                 java
		  102            bala                 java
		  103            akash                python
		  103            ram                  postgres
		  104            manoj                oracle_dba
		  105            sam                  testing
		  105            vicky                java

	  8 rows selected.
2. UNION ALL:

It returns all rows selected by either query


	Select * from tesdb01
	Union all
	Select * from tesdb02;
	SQL> select * from tesdb01 union all select * from tesdb02;

	COURES_ID           NAME                  COURSE_NAME
	----------    --------------------     --------------------
		  101           arun                    oracle_dba
		  102           bala                    java
		  103           akash                   python
		  104           manoj                   oracle_dba
		  105           vicky                   java
		  101           arun                    oracle_dba
		  102           babu                    java
		  103           ram                     postgres
		  104           manoj                   oracle_dba
		  105           sam                     testing

	10 rows selected.
3. INTERSECT:

It returns all distinct rows selected by both query


	select * from tesdb01
	Intersect
	Select * from tesdb02;
	SQL> select * from tesdb01 intersect select * from tesdb02;

	COURES_ID           NAME              COURSE_NAME
	----------    -------------------- --------------------
		  101           arun              oracle_dba
		  104           manoj             oracle_dba
4.MINUS:

It returns all distinct rows selected by first query only. 


	Select * from tesdb01
	Minus
	Select * From tesd02
	SQL> select * from tesdb01 minus select * from tesdb02;

	COURES_ID	NAME		COURSE_NAME
	---------	----------	-------------
	  102		bala		java
	  103		akash		python
	  105		vicky		java
(SQL - SubQueries)