Left Join

SQL LEFT JOIN

The LEFT JOIN returns all rows from the table A, whether or not there is a match with table B.

SELECT column_name(s)
FROM A_table LEFT JOIN B_table
ON A_table.column_name = B_table.column_name;

ID	NAME	DURATION	PRICE
1	SQL	5	200
2	T-SQL	7	700
3	MySQL	5	600
4	PL/SQL	7	800
5	PostgreSQL	6	500

ID	NAME	PRICE	ID_TC
1	PostgreSQL certification	800	5
2	SQL certification	350	1
3	T-SQL certification	1000	2

SELECT t.ID,t.NAME,t.PRICE
FROM Training_Course t LEFT JOIN Certifications c 
ON t.ID = c.ID_TC ;