SQL Tutorial #19 Introduction to joins in SQL

A JOIN clause is used to combine rows from two or more tables, based on a related column between them.

Use an inner join when: You don’t need to show all the records from the first table or all the records from the second table.

Use a left join when: You need to show all the records from the first table, but you don’t need to show all the records from the second table.

Use a right join when: You don’t need to show all the records from the first table, but you do need to show all the records from the second table.

Use a full join when: You need to show all the records from the first and second tables, and you need to join the tables based on one or more columns.

Use a cross join when: You need to show all the records from the first and second tables, but you don’t need to join the tables based on one or more columns.