What to know about the SQL JOIN clause

The JOIN clause is used to join two or more tables together based on a matching column between the tables. The result set combines records from each table based on the matching column. The column(s) used to join tables together are typically referred to as ‘Primary’ or ‘Foreign’ keys.

There are four major types of joins used in SQL syntax:

1. INNER JOIN

2. LEFT JOIN

3. RIGHT JOIN

4. FULL (OUTER) JOIN

‘INNER’ and ‘OUTER’ keywords in the JOIN clauses are optional and not required in the syntax.

(INNER) JOIN

LEFT JOIN

RIGHT JOIN

FULL (OUTER) JOIN