Listing Common Data of Two Tables Based on Join Key in SQL

A guide on how to use SQL statements to list common data between two tables based on join keys. This article helps you better understand how to use `INNER JOIN` to combine data from two tables.

In this article, we will explore how to query common data between two tables in SQL using the INNER JOIN statement. This statement allows us to combine data from two tables based on join conditions, making it easier to manage and analyze data.

SQL code

SELECT a.*, b.*
FROM TableA a
INNER JOIN TableB b ON a.common_key = b.common_key;

Detailed explanation

SELECT a.*, b.*: Selects all columns from both TableA and TableB.
FROM TableA a: Specifies the TableA and assigns it an alias a.
INNER JOIN TableB b: Performs an INNER JOIN with TableB and assigns it an alias b.
ON a.common_key = b.common_key: The join condition between the two tables based on the common key.

System Requirements:

SQL Server, MySQL, PostgreSQL, or any database management system that supports SQL.

How to install the libraries needed to run the SQL code above:

No additional libraries need to be installed, just ensure you have a database and two pre-existing tables.

Tips:

Ensure that the join key between the two tables is unique to avoid duplicate data in the results.
Use indexes on join keys to optimize query performance.

Tags: SQL