Left Outer join in MariaDB

LEFT JOIN
The MariaDB Left Outer Join query returns all the rows from the Left table for the specified fields. For the Right table, it only returns those rows where the join condition is met.

Syntax:

SELECT expr_1, expr_2, ... expr_n  
FROM table_1   
LEFT JOIN table_2  
ON join_predicate;

Example:
Players Table:

ID	NAME	         SPORTS
1	Sachin	         Cricket
2	Dhoni	         Cricket
3	Sunil	         Football
4	Srikanth	 Badminton
5	Mary	         Boxing

Trainers Table:

TRAINER_ID	TRAINER_NAME	TRAINER_SPORTS
101	        Bond	        Football
102	        Smith	        Badminton
103	        Brand	        Boxing

Query:

SELECT players.id, players.name, trainers.trainer_id  
FROM players  
LEFT JOIN trainers  
ON players.sports = trainers.trainer_sports;

Output:

ID	NAME	        TRAINER_ID
1	Sachin	        NULL
2	Dhoni	        NULL
3	Sunil	        101
4	Srikanth	102
5	Mary	        103

Explanation:
The PLAYERS and the TRAINERS are the already existing tables. All the records for the selected fields from the PLAYERS table will be added to the result set. And only those records from the selected fields of the TRAINERS table will be added to the result set which are satisfying the join conditions.