What are different JOINS used in SQL?

4 major types of Joins are used while working on multiple tables in SQL databases:

INNER JOIN: It is also known as SIMPLE JOIN which returns all rows from BOTH tables when it has at least one matching column.

Syntax:

SELECT column_name(s) 
 FROM table_name1 
 INNER JOIN table_name2 
 ON column_name1=column_name2;

LEFT JOIN (LEFT OUTER JOIN): This join returns all rows from the LEFT table and its matched rows from a RIGHT table.

Syntax:

SELECT column_name(s)
 FROM table_name1
 LEFT JOIN table_name2
 ON column_name1=column_name2;

RIGHT JOIN (RIGHT OUTER JOIN): This joins returns all rows from the RIGHT table and its matched rows from the LEFT table.

Syntax:

SELECT column_name(s)
FROM table_name1
RIGHT JOIN table_name2
ON column_name1=column_name2;

FULL JOIN (FULL OUTER JOIN): This joins returns all results when there is a match either in the RIGHT table or in the LEFT table.

Syntax:

SELECT column_name(s)
 FROM table_name1
 FULL OUTER JOIN table_name2
 ON column_name1=column_name2;