FAQ : What is Equi-JOIN and Non-Equi JOIN in SQL

What is Equi-Join?

When a JOIN is made on Exact match between two columns it is called equi-Join.
Eg.
SELECT A.*
FROM EMPLOYEES A, EMPLOYEE_SAL B
WHERE A.EMP_ID=B.EMP_ID
OR
SELECT A.*
FROM EMPLOYEES A
INNER JOIN EMPLOYEE_SAL B
ON A.EMP_ID=B.EMP_ID
Both the queries mentioned above can be considered as Equi-join.

What is NON-Equi Join.

If you use any other comparison operator other than = in JOIN condition, it is called NON-Equi JOIN
SELECT A.*
FROM EMPLOYEES A, EMPLOYEE_SAL B
WHERE A.EMP_ID <> B.EMP_ID