SQL Joins

SQL joins are used to combine rows from two or more tables based on a related column between them. This allows you to retrieve data from multiple tables in a single query.

Types of SQL joins:

INNER JOIN

Returns rows when there is at least one match in both tables. Example:

SELECT *
FROM table1
INNER JOIN table2
ON table1.column_name = table2.column_name;

LEFT JOIN

Also - LEFT OUTER JOIN. Returns all rows from the left table and the matched rows from the right table. If there is no match, NULL values are returned. Example:

SELECT *
FROM table1
LEFT JOIN table2
ON table1.column_name = table2.column_name;

RIGHT JOIN

Also - RIGHT OUTER JOIN. Returns all rows from the right table and the matched rows from the left table. If there is no match, NULL values are returned. Example:

SELECT *
FROM table1
RIGHT JOIN table2
ON table1.column_name = table2.column_name;

FULL JOIN

Also - FULL OUTER JOIN. Returns rows when there is a match in one of the tables. It combines the results of both LEFT JOIN and RIGHT JOIN. Example:

SELECT *
FROM table1
FULL JOIN table2
ON table1.column_name = table2.column_name;