SQL INNER JOIN with Examples

 Introduction

The INNER JOIN is the most common type of SQL JOIN. It retrieves rows that have matching values in both tables. If no match is found, the row will not appear in the result set.

Step 1: Basic Syntax

SELECT table1.column, table2.column

FROM table1

INNER JOIN table2

ON table1.common_column = table2.common_column;

➡️ common_column is the field that exists in both tables and links them together.

Step 2: Example with Customers and Orders

Imagine you have two tables:

customers

customer_id name

1 Ali

2 Mona

3 Samir

orders

order_id customer_id product

101 1 Laptop

102 2 Phone

103 1 Keyboard

Query:

SELECT customers.name, orders.product

FROM customers

INNER JOIN orders

ON customers.customer_id = orders.customer_id;

Result:

name product

Ali Laptop

Mona Phone

Ali Keyboard

Step 3: Why Use INNER JOIN?

To get only related data between two (or more) tables.

Reduces clutter by excluding non-matching rows.

Very useful in reporting and analysis.

Conclusion

The INNER JOIN is your go-to when you only want records that exist in both tables. With practice, you can extend INNER JOIN to multiple tables for more complex queries.