Joins

There are different type of joins in SQL

1.Inner Join-Return all the values if there is a match in both the table.

2.Outer join

-left outer join-Return all the values from left table and the values matched from the right table.

-right outer join-Return all the values from the right table and the values matched from the left table.

3.Self join-In this we divide a single table to different table using alias and join them it behave as the two tables but actually is one.

Inner join

SELECT column_name(s)
FROM table1
INNER JOIN table2
ON table1.column_name=table2.column_name;

Left outer join

SELECT column_name(s)
FROM table1
LEFT JOIN table2
ON table1.column_name=table2.column_name;

Right outer join

SELECT column_name(s)
FROM table1
RIGHT JOIN table2
ON table1.column_name=table2.column_name;

Self join

SELECT e1.employee_name
FROM employee e1, employee e2
WHERE e1.employee_location = e2.employee_location
AND e2.employee_name="Joe";