---
title: "Left Vs Right Outer Join Which is Better"
description: "Ideas for DB2 developers which JOIN is better LEFT or RIGHT. Read now."
url: https://srinimf.com/2018/06/09/real-idea-left-outer-join-you-always-need-to-code-in-db2-read-now/
date: 2018-06-09
modified: 2026-10-10
author: "Srini"
image: https://i0.wp.com/srinimf.com/wp-content/uploads/2018/06/sql-performance-tuning.jpg?fit=1200%2C700&ssl=1
categories: ["SQL"]
tags: ["DB2 Performance tips", "Db2 Tips", "Right or Left which Join better"]
type: post
lang: en
---

# Left Vs Right Outer Join Which is Better

The concept of [JOINS in SQL](https://srinimf.com/2014/09/10/how-to-use-multiple-joins-in-db2/) is to get data from multiple Tables. [In DB2](https://srinimf.com/2012/07/10/sql-db2-and-joins/), you can find two [types of](https://srinimf.com/2014/05/17/imsdb-different-ssa-types/) outer joins – **LEFT** outer and **RIGHT** outer JOINS.

Related[How to Write SQL Queries Efficiently in DB2](https://srinimf.com/2014/10/12/db2-sql-with-joins-performance/)

> T[here is](https://srinimf.com/2014/09/23/db2-performance-tuning-explain-plan/) no difference between a left outer join and right outer join other than where the starting driver table is coded

Related[SQL and PySpark: Efficient String Slicing Techniques](https://srinimf.com/2024/10/03/etl-sql-query-and-pyspark-string-slicing-2-top-examples/)

**LEFT Outer JOIN**

Related[Mainframe Vs Unix Top Differences](https://srinimf.com/2015/11/11/unix-and-mainframe-basic-differences/)

SELECT D.DEPTNO, D.DEPTNAME, D.MGRNO,

E.LASTNAME

FROM DEPT D LEFT JOIN

EMP E ON D.MGRNO = E.EMPNO

**Right Outer JOIN**

SELECT D.DEPTNO, D.DEPTNAME, D.MGRNO,

E.LASTNAME

FROM EMP E RIGHT JOIN

DEPT D ON D.MGRNO = E.EMPNO

When you give LEFT join, the driver table will be left side one. When you give RIGHT join, then the driver table will be right side one.

**LEFT outer Join [is Better](https://srinimf.com/2016/11/23/tokenization-encryption/) Why**

- DB2 itself converts RIGHT outer JOIN into LEFT outer JOIN during SQL query processing
- So to avoid confusion and save CPU time always code only LEFT OUTER join
- This improves your SQL query performance

**Also read**

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