SQL INNER JOIN OR JOIN

When you want to combine two or more tables in SQL then commonly you use SQL JOIN or SQL INNER JOIN.

For example EMPLOYEE Table has

EMP_ID	EMP_NAME	HIRE_DATE	SALARY	DEPT_ID
1	Roger Fed	2001-05-01	5000	4
2	Djoker Nova	2002-07-15	6500	1
3	Stef Graph	2005-10-18	8000	5
4	Mart Hingis	2007-01-03	7200	3
5	Andre Duplesi	2008-06-24	5600	null

DEPARTMENT Table has

DEPT_ID	DEPT_NAME
1	French Open
2	Wimbledon
3	US Open
4	Aus Open
5	Olympics Games

Now lets try a SELECT JOIN statement

SELECT DEPT_ID, DEPT_NAME, EMP_NAME, SALARY   

   FROM  EMPLOYEE e, DEPARTMENT d

   WHERE e.DEPT_ID =d.DEPT_ID;  

The Output will look like this:

DEPT_ID	DEPT_NAME	EMP_NAME	SALARY
4	Aus Open	Roger Fed	5000
1	French Open	Djoker Nova	6500
5	Olympics Games	Stef Graph	8000
3	US Open	Mart Hingis	7200

INNER JOIN select all records from both tables as long as there is a match between the columns in these 2 tables. If no match in DEPARTMENT table found w.r.t EMPLOYEE table then those records of DEPARTMENT table wont be shown.

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