What is SQL FULL OUTER JOIN

The SQL FULL OUTER JOIN is a type of outer join that combines all the rows from the left table and right table. It add all the matching rows from both the tables. If there is no match in both the table, it return null value for the missing cell.

SQL FULL OUTER JOIN Image

In order to get the full outer join output in SQL, the query result finds all the rows from the first table and the second table and put all the matching rows from the these table.

One thing you should note here that if there is no matching values in both the tables it returns a null value.

How to Use FULL OUTER JOIN in SQL

Now, if you want to understand the how to use full outer join in SQL, you have to use the two tables and the syntax given below. Both the tables are required from where you have to take all the rows for the matching columns.

Syntax

The above syntax result out all the rows from both the tables in the SQL query. It gives you output for all the matching column rows from both the table.

It also finds non-matching value and returns out null value.

Example of SQL RIGHT OUTER JOIN

Now, let us create the two tables for Purchaser and Seller as given below to understand the example of full outer join in SQL server.

Below are the examples that contains the statement and the output of the full outer join of the given tables.

SQL FULL OUTER Join Example Using the Select Statement

There are two tables, the first table is Purchaser table and second is the Seller table.

The first table contains the list of the purchasers.
Table 1: Purchaser

Purchaser_ID Purchaser_Name Plot_No Service_Id
1 Sam 12 1001
2 Pill 13 1002
3 Don 14 1003
4 Brock 15 1004

The second table contains the list of sellers.
Table 2: Seller

Id Seller_Name Seller_Email
1001 Big Show big@gmail.com
1002 Gem gem@gmail.com
1003 Matt matt@gmail.com

Now, let’s combine the above two tables using the example given below.

Example

Output

Service_Id Seller_Name Purchaser_Name Plot_No
1001 Big Show Sam 12
1002 Gem Pill 13
1003 Matt Don 14
1004 Null Brock 15

You must also read.

Reference
Outer Join

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