What is full outer join?

An full outer join is a method of combining tables so that the result includes unmatched rows of both tables. If you are joining two tables and want the result set to include unmatched rows from both tables, use a FULL OUTER JOIN clause. The matching is based on the join condition.

What is difference between full join and full outer join?

Full Outer Join returns all the rows from both the table….Differences between Left Outer Join, Right Outer Join, Full Outer Join :

Left Outer Join Right Outer Join Full Outer Join
Unmatched data of the right table is lost Unmatched data of the left table is lost No data is lost

How do I join two tables in full outer?


  1. Syntax of FULL OUTER JOIN. The syntax of FULL OUTER JOIN is: SELECT columns FROM table1 FULL OUTER JOIN table2 ON table1.column_name = table2.column_name;

Is outer and full join same?

The FULL OUTER JOIN keyword returns all records when there is a match in left (table1) or right (table2) table records. Tip: FULL OUTER JOIN and FULL JOIN are the same.

How many rows in full outer join?

A FULL OUTER JOIN returns one distinct row from each table—unlike the CROSS JOIN which has multiple.

Does full outer join remove duplicates?

With help of it you can eliminate the duplicates on selected columns. @chirag-mehta – Yes, my sql with look like that. My actual code has Left Outer, Right Outer. etc.

In which case should you use a full outer join?

We use a FULL OUTER JOIN in Oracle when we want all unmatched data from both tables. Explanation: Oracle9i also makes it possible for you to easily execute a full outer join, including all records from the tables that would have been displayed if you had used both LEFT OUTER JOIN or RIGHT OUTER JOIN clauses.

Why use a full outer join?

FULL JOIN: An Introduction Unlike INNER JOIN , a FULL JOIN returns all the rows from both joined tables, whether they have a matching row or not. Hence, a FULL JOIN is also referred to as a FULL OUTER JOIN . A FULL JOIN returns unmatched rows from both tables as well as the overlap between them.

Is full outer join faster than union?

However, answering your question using UNION ALL will be faster, as it simply passes the first SELECT statement, and then parses the second SELECT statement and adds the results to the end of the output table.

Does full outer join have duplicates?

Inner join will give you the records that have the same values in the joined columns between the 2 tables. From what you are saying, the 2 tables you are comparing are more or less the same, and full outer join giving you records from both tables, chances are you are going to get a lot of duplicates.

In which case you use full outer join?