search
HomeDatabaseMysql TutorialMastering SQL Joins: LEFT JOIN vs RIGHT JOIN Explained with Examples

Mastering SQL Joins: LEFT JOIN vs RIGHT JOIN Explained with Examples

Here’s a clean and structured explanation of LEFT JOIN and RIGHT JOIN using tables in a readable way:


Understanding LEFT JOIN and RIGHT JOIN in SQL

LEFT JOIN and RIGHT JOIN are types of SQL OUTER JOINs. They are used to fetch data from two tables based on a matching condition, while also including unmatched rows from one of the tables.


1. LEFT JOIN

  • The LEFT JOIN returns all rows from the left table, and the matched rows from the right table.
  • If there is no match, the result contains NULL for the columns of the right table.

Syntax:

SELECT columns
FROM table1
LEFT JOIN table2
ON table1.column = table2.column;

Example:

Table: Employees

EmployeeID Name DepartmentID
1 Alice 101
2 Bob 102
3 Charlie NULL
4 Diana 104

Table: Departments

DepartmentID DepartmentName
101 HR
102 IT
103 Finance

Query:

SELECT Employees.Name, Departments.DepartmentName
FROM Employees
LEFT JOIN Departments
ON Employees.DepartmentID = Departments.DepartmentID;

Result:

Name DepartmentName
Alice HR
Bob IT
Charlie NULL
Diana NULL
  • All rows from Employees are included.
  • Rows without a match in Departments (like Charlie and Diana) show NULL.

2. RIGHT JOIN

  • The RIGHT JOIN returns all rows from the right table, and the matched rows from the left table.
  • If there is no match, the result contains NULL for the columns of the left table.

Syntax:

SELECT columns
FROM table1
RIGHT JOIN table2
ON table1.column = table2.column;

Example:

Using the same tables Employees and Departments.

Query:

SELECT Employees.Name, Departments.DepartmentName
FROM Employees
RIGHT JOIN Departments
ON Employees.DepartmentID = Departments.DepartmentID;

Result:

Name DepartmentName
Alice HR
Bob IT
NULL Finance
  • All rows from Departments are included.
  • Rows without a match in Employees (like Finance) show NULL.

Key Differences


Feature LEFT JOIN RIGHT JOIN
Feature LEFT JOIN RIGHT JOIN
Included Rows All rows from the left table. All rows from the right table.
Unmatched Rows NULL for unmatched right table. NULL for unmatched left table.
Primary Use Ensure all rows from the left table appear. Ensure all rows from the right table appear.
Included Rows
All rows from the left table. All rows from the right table.

Unmatched Rows

NULL for unmatched right table. NULL for unmatched left table.
Primary Use Ensure all rows from the left table appear. Ensure all rows from the right table appear.
  • When to Use?
  • LEFT JOIN
  • : Use when you want all data from the left table, regardless of matches in the right table.

RIGHT JOIN

: Use when you want all data from the right table, regardless of matches in the left table.


By presenting tables neatly and explaining key concepts with examples, the structure remains easy to understand and visually appealing.

Hi, I'm Abhay Singh Kathayat! I am a full-stack developer with expertise in both front-end and back-end technologies. I work with a variety of programming languages and frameworks to build efficient, scalable, and user-friendly applications. Feel free to reach out to me at my business email: kaashshorts28@gmail.com.

The above is the detailed content of Mastering SQL Joins: LEFT JOIN vs RIGHT JOIN Explained with Examples. For more information, please follow other related articles on the PHP Chinese website!

Statement
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn
How Do I Drop or Modify an Existing View in MySQL?How Do I Drop or Modify an Existing View in MySQL?May 16, 2025 am 12:11 AM

TodropaviewinMySQL,use"DROPVIEWIFEXISTSview_name;"andtomodifyaview,use"CREATEORREPLACEVIEWview_nameASSELECT...".Whendroppingaview,considerdependenciesanduse"SHOWCREATEVIEWview_name;"tounderstanditsstructure.Whenmodifying

MySQL Views: Which design patterns can I use with it?MySQL Views: Which design patterns can I use with it?May 16, 2025 am 12:10 AM

MySQLViewscaneffectivelyutilizedesignpatternslikeAdapter,Decorator,Factory,andObserver.1)AdapterPatternadaptsdatafromdifferenttablesintoaunifiedview.2)DecoratorPatternenhancesdatawithcalculatedfields.3)FactoryPatterncreatesviewsthatproducedifferentda

What Are the Advantages of Using Views in MySQL?What Are the Advantages of Using Views in MySQL?May 16, 2025 am 12:09 AM

ViewsinMySQLarebeneficialforsimplifyingcomplexqueries,enhancingsecurity,ensuringdataconsistency,andoptimizingperformance.1)Theysimplifycomplexqueriesbyencapsulatingthemintoreusableviews.2)Viewsenhancesecuritybycontrollingdataaccess.3)Theyensuredataco

How Can I Create a Simple View in MySQL?How Can I Create a Simple View in MySQL?May 16, 2025 am 12:08 AM

TocreateasimpleviewinMySQL,usetheCREATEVIEWstatement.1)DefinetheviewwithCREATEVIEWview_nameAS.2)SpecifytheSELECTstatementtoretrievedesireddata.3)Usetheviewlikeatableforqueries.Viewssimplifydataaccessandenhancesecurity,butconsiderperformance,updatabil

MySQL Create User Statement: Examples and Common ErrorsMySQL Create User Statement: Examples and Common ErrorsMay 16, 2025 am 12:04 AM

TocreateusersinMySQL,usetheCREATEUSERstatement.1)Foralocaluser:CREATEUSER'localuser'@'localhost'IDENTIFIEDBY'securepassword';2)Foraremoteuser:CREATEUSER'remoteuser'@'%'IDENTIFIEDBY'strongpassword';3)Forauserwithaspecifichost:CREATEUSER'specificuser'@

What Are the Limitations of Using Views in MySQL?What Are the Limitations of Using Views in MySQL?May 14, 2025 am 12:10 AM

MySQLviewshavelimitations:1)Theydon'tsupportallSQLoperations,restrictingdatamanipulationthroughviewswithjoinsorsubqueries.2)Theycanimpactperformance,especiallywithcomplexqueriesorlargedatasets.3)Viewsdon'tstoredata,potentiallyleadingtooutdatedinforma

Securing Your MySQL Database: Adding Users and Granting PrivilegesSecuring Your MySQL Database: Adding Users and Granting PrivilegesMay 14, 2025 am 12:09 AM

ProperusermanagementinMySQLiscrucialforenhancingsecurityandensuringefficientdatabaseoperation.1)UseCREATEUSERtoaddusers,specifyingconnectionsourcewith@'localhost'or@'%'.2)GrantspecificprivilegeswithGRANT,usingleastprivilegeprincipletominimizerisks.3)

What Factors Influence the Number of Triggers I Can Use in MySQL?What Factors Influence the Number of Triggers I Can Use in MySQL?May 14, 2025 am 12:08 AM

MySQLdoesn'timposeahardlimitontriggers,butpracticalfactorsdeterminetheireffectiveuse:1)Serverconfigurationimpactstriggermanagement;2)Complextriggersincreasesystemload;3)Largertablesslowtriggerperformance;4)Highconcurrencycancausetriggercontention;5)M

See all articles

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Roblox: Bubble Gum Simulator Infinity - How To Get And Use Royal Keys
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
Nordhold: Fusion System, Explained
1 months agoBy尊渡假赌尊渡假赌尊渡假赌
Mandragora: Whispers Of The Witch Tree - How To Unlock The Grappling Hook
4 weeks agoBy尊渡假赌尊渡假赌尊渡假赌
Clair Obscur: Expedition 33 - How To Get Perfect Chroma Catalysts
2 weeks agoBy尊渡假赌尊渡假赌尊渡假赌

Hot Tools

Safe Exam Browser

Safe Exam Browser

Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

SublimeText3 English version

SublimeText3 English version

Recommended: Win version, supports code prompts!

MinGW - Minimalist GNU for Windows

MinGW - Minimalist GNU for Windows

This project is in the process of being migrated to osdn.net/projects/mingw, you can continue to follow us there. MinGW: A native Windows port of the GNU Compiler Collection (GCC), freely distributable import libraries and header files for building native Windows applications; includes extensions to the MSVC runtime to support C99 functionality. All MinGW software can run on 64-bit Windows platforms.

mPDF

mPDF

mPDF is a PHP library that can generate PDF files from UTF-8 encoded HTML. The original author, Ian Back, wrote mPDF to output PDF files "on the fly" from his website and handle different languages. It is slower than original scripts like HTML2FPDF and produces larger files when using Unicode fonts, but supports CSS styles etc. and has a lot of enhancements. Supports almost all languages, including RTL (Arabic and Hebrew) and CJK (Chinese, Japanese and Korean). Supports nested block-level elements (such as P, DIV),

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools