JOIN is an SQL clause used to query and access data from multiple tables, based on logical relationships between those tables.
Check out the Joins Site for a visual and interactive way to learn about Joins!
The SQL INNER JOIN returns the records where table1 and table2 intersect.
This join returns all the rows of the table on the left side of the join and matches rows for the table on the right side of the join. For the rows for which there is no matching row on the right side, the result-set will contain null.
RIGHT JOIN is similar to LEFT JOIN. This join returns all the rows of the table on the right side of the join and matching rows for the table on the left side of the join. For the rows for which there is no matching row on the left side, the result-set will contain null.
A FULL JOIN combines the results of both LEFT JOIN and RIGHT JOIN. The result-set will contain all the rows from both tables. For the rows for which there is no match, the result-set will contain NULL values.
