SQL LEFT JOIN

SQL LEFT JOIN Syntax

SELECT column_name1, column_name2, ...column_nameN
FROM table_name1
LEFT JOIN table_name2
ON table1.column_name1 = table2.column_name1;

SELECT column_name1, column_name2, ...column_nameN
FROM table_name1
LEFT OUTER JOIN table_name2
ON table1.column_name1 = table2.column_name1;

Note: In some databases LEFT JOIN is called LEFT OUTER JOIN.

Sample Database Table - Books

Sample Database Table - BookOrder

Note:- There must be a common columns while selecting columns from multiple tables. In the "BookOrder" and "Books" both tables contains a common column called "ID".

SQL LEFT JOIN - Example

Notice that the "BookID" column in the "Books" table refers to the "BookID" in the "BookOrder" table. The relationship between the two tables above is the "BookID" column.

Then, if we run the following SQL statement (that contains an LEFT JOIN):

SELECT 
Books.BookID, Books.BookName, BookOrder.Qty, BookOrder.OrderDate
FROM Books
LEFT JOIN BookOrder
ON Books.BookID = BookOrder.BookID;

The result of above query is:

Note: The SQL LEFT JOIN keyword returns all the records from the left side table (BookOrder), even if there are no matches in the right side table (Books).