SQL FULL JOIN Vs LEFT JOIN Clause

The distinction between a FULL JOIN and an LEFT JOIN will be discussed in this session.


SQL FULL JOIN Clause

FULL JOIN can be thought of as a combination of LEFT JOIN and RIGHT JOIN.

This query will return a single row for each unique entry in either the right or left tables.

Example: Full join clause

SELECT Product.name, Product.no,
FROM Product
FULL OUTER JOIN Customer on Product.no = Customer.no

SQL LEFT JOIN Clause

This will involve adding left table entries regardless of whether or not a comparable record exists in the right table.

Example: The Customer and order table is the left table in the query below.

CID Name Gender City
C-1 Keshavan Male Madurai
C-2 Harish Karthik Female Hyderbhad
OrderNo CID Amount OrderDate
1 C-1 4000 2004/08/20 18:56:46
2 C-2 8000 1998/05/25 20:34:47
SELECT Author.AuthorName,Author.AID ,Book.BookName,Book.AID
FROM Author
LEFT JOIN Book
ON Author.AID = Book.AID;

Output As a result, the output will be,

authorname ab_author.aid bookname ab_book.aid
Hanumanthan A-1 Learing Sql Server T-Sql A-1
Hanumanthan A-1 SQL Visual Quickstart A-1
Hanumanthan A-1 The Database Language SQL A-1
Ranjani Mai A-2 Programming with PL/SQL for Beginners A-2

SQL Differece Between LEFT JOIN AND FULL JOIN Clause

There are 3 main contrast in left join & full join clause that are in below table:-

LEFT JOIN FULL JOIN
Gets all the rows from the left-hand table. Retrieves all rows from both tables.
Inner Join +all the rows from the left table that aren't matched. Inner Join +all the rows from the left table that aren't matched +all the rows from the right table that aren't matched
The right table's unmatched data is lost Neither information is lost.