#        
## Introduction to `FULL OUTER JOIN`
In **`FULL OUTER JOIN`**, we join two tables' values with a common attribute. The non-matching records are joined with the ```NULL``` value for both tables. 

In `FULL OUTER JOIN`, the following happens:

1. First, an #key# inner join: In inner join, we match two table entries on some matching condition. #key# is performed.
2. Then, the rest of the entries in both tables are joined with ```NULL``` values.



## Syntax
The syntax of the ```FULL OUTER JOIN``` query is as follows:

SELECT column_name(s) FROM table1 
  FULL OUTER JOIN table2 
  ON conditional_expression;

We can better understand this with an example.

## Example
Consider the following tables:

COMPANY

align-center

DEPARTMENT

SELECT EMP_ID, NAME, DEPT FROM COMPANY 
  FULL OUTER JOIN DEPARTMENT
  ON COMPANY.ID = DEPARTMENT.EMP_ID;

## Explanation

The above query will join the values in the `id` column of the COMPANY table with the values of the ```emp_id``` column of the DEPARTMENT table. The rest of the entries in both tables will join with ```NULL``` values.


The above `FULL OUTER JOIN` query will produce the following table.

Result table

postgresql.tar.gz

What is FULL OUTER JOIN in PostgreSQL?

 Introduction to FULL OUTER JOIN In FULL OUTER JOIN, we join two tables  values with a common attribute. The non-matching records are joined with the NULL value for both tables. In FULL OUTER JOIN, the following happens:  First, an inner joinIn inner join, we match two table entries on some matching condition. is performed. Then, the rest of the entries in both tables are joined with NULL values.  

id	name	age	address	salary	join_date
1	Paul	32	London	20000	2001-08-13
2	Rock	23	Texas	25000	2002-03-24
3	Allen	27	Norway	22500	2004-02-02
4	Teddy	31	Houston	27500	2000-04-11

id	dept	emp_id
1	IT	1
2	Accounts	2
3	Marketing	5

emp_id	name	dept
1	Paul	IT
2	Rock	Accounts
5		Marketing
	Allen
	Teddy