MariaDB LEFT OUTER JOIN is used to return all rows from the left-hand table specified in the ON condition and only those rows from the other table where the joined condition is satisfied.
LEFT OUTER JOIN is also called LEFT JOIN.
Syntax:
SELECT columns
FROM table1
LEFT [OUTER] JOIN table2
ON table1.column = table2.column;
Example
We have two tables' sites and pages:
Sites table:
site_id site_name
100 javatpoint.com
200 Facebook.com
300 Yahoo.com
400 Google.com
Pages table:
page_id site_id page_title
1 100 MariaDB
2 100 MySQL
3 200 Java interview questions
4 300 Software testing
5 500 Flight booking
Now execute the following commands:
SELECT sites.site_id, sites.site_name, pages.page_id, pages.page_title FROM sites LEFT JOIN pages ON sites.site_id= pages.site_id
Output:
site_id site_name page_id page_title
100 javatpoint 1 MariaDB
100 javatpoint 2 MySQL
200 Facebook.com 3 Java interview questions
300 Yahoo.com 4 Software testing
400 Google.com null null
Site_name Google.com is also included because of LEFT JOIN.
