---
title: "What is a \"join\"?"  
description: "What is a \"join\"?"  
author: "Pushpendra Singh"  
published: 2010-10-25  
updated: 2020-09-24  
canonical: https://www.mindstick.com/interview/89/what-is-a-join  
category: "mssql server"  
tags: ["mssql server"]  
reading_time: 2 minutes  

---

# What is a "join"?

The JOIN keyword is used in an SQL statement to query data from two or more tables, based on a relationship between certain columns in these tables. Tables in a database are often related to each other with keys.\
A primary key is a column (or a combination of columns) with a unique value for each row. Each primary key value must be unique within the table. The purpose is to bind data together, across tables, without repeating all of the data in every table.\
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Types of join:\
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Inner Join\
Outer Join\
Full Join \
Right Join\
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## Answers

### Answer by Amit Singh

The JOIN keyword is used in an SQL statement to query data from two or more tables, based on a relationship between certain columns in these tables. Tables in a database are often related to each other with keys.\
A primary key is a column (or a combination of columns) with a unique value for each row. Each primary key value must be unique within the table. The purpose is to bind data together, across tables, without repeating all of the data in every table.\
\
Types of join:\
\
Inner Join\
Outer Join\
Full Join \
Right Join\
\
\
\


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Original Source: https://www.mindstick.com/interview/89/what-is-a-join

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