SQL INNER JOIN — How to Match Rows from Two Tables

What Is SQL INNER JOIN?

The SQL INNER JOIN keyword selects records that have matching values in both tables. If a row in the left table has no corresponding match in the right table, that row is excluded from the result. Similarly, unmatched rows in the right table are also excluded.

Think of it like finding common friends between two people — only the names that appear in both lists are returned. As you learned in Chapter 20: SQL Joins Introduction, JOINs let you combine data from multiple tables. INNER JOIN is the most restrictive and most frequently used type.

SQL INNER JOIN Syntax

Here is the basic SQL INNER JOIN syntax:

SELECT column_name(s)
FROM table1
INNER JOIN table2
ON table1.column_name = table2.column_name;

The ON clause specifies the condition used to match rows between the two tables. This is usually a primary key and foreign key relationship.

Sample Tables for Examples

We will use the Customers and Orders tables throughout this chapter. These are the same tables used across our SQL Tutorial course.

+----+----------------+-----------+---------+
| ID | CustomerName   | City      | Country |
+----+----------------+-----------+---------+
| 1  | Rahul Sharma   | Mumbai    | India   |
| 2  | Sarah Johnson  | New York  | USA     |
| 3  | Amit Patel     | Delhi     | India   |
| 4  | Lisa Chen      | Singapore | SG      |
| 5  | David Brown    | London    | UK      |
+----+----------------+-----------+---------+

+----+------------+------------+--------+---------+
| ID | CustomerID | OrderDate  | Amount | Status  |
+----+------------+------------+--------+---------+
| 1  | 1          | 2026-01-15 | 250.00 | Shipped |
| 2  | 2          | 2026-01-18 | 430.00 | Pending |
| 3  | 1          | 2026-02-01 | 180.00 | Shipped |
| 4  | 3          | 2026-02-10 | 520.00 | Shipped |
| 5  | 4          | 2026-03-05 | 310.00 | Pending |
+----+------------+------------+--------+---------+

Notice that Customer ID 5 (David Brown) has no orders, and every order belongs to an existing customer.

SQL INNER JOIN Example

Let us write an SQL INNER JOIN example that retrieves each customer’s name along with their order amount:

SELECT Customers.CustomerName, Orders.Amount, Orders.OrderDate
FROM Customers
INNER JOIN Orders
ON Customers.ID = Orders.CustomerID;

+----------------+--------+------------+
| CustomerName   | Amount | OrderDate  |
+----------------+--------+------------+
| Rahul Sharma   | 250.00 | 2026-01-15 |
| Sarah Johnson  | 430.00 | 2026-01-18 |
| Rahul Sharma   | 180.00 | 2026-02-01 |
| Amit Patel     | 520.00 | 2026-02-10 |
| Lisa Chen      | 310.00 | 2026-03-05 |
+----------------+--------+------------+

Notice that David Brown (Customer ID 5) does not appear in the result because he has no matching row in the Orders table. This is exactly how INNER JOIN works — it only returns matched rows.

SQL INNER JOIN with Aliases

Writing full table names can get repetitive. As you learned in Chapter 19: SQL Aliases, you can use short aliases to simplify your queries:

SELECT c.CustomerName, o.Amount, o.Status
FROM Customers AS c
INNER JOIN Orders AS o
ON c.ID = o.CustomerID;

This produces the same result as the previous query but is much cleaner to read and write.

SQL INNER JOIN with WHERE Clause

You can combine INNER JOIN with a WHERE clause to filter joined results further:

SELECT c.CustomerName, o.Amount, o.Status
FROM Customers AS c
INNER JOIN Orders AS o
ON c.ID = o.CustomerID
WHERE o.Status = 'Shipped';

+----------------+--------+---------+
| CustomerName   | Amount | Status  |
+----------------+--------+---------+
| Rahul Sharma   | 250.00 | Shipped |
| Rahul Sharma   | 180.00 | Shipped |
| Amit Patel     | 520.00 | Shipped |
+----------------+--------+---------+

The JOIN matches the rows first, and then the WHERE clause filters only the shipped orders.

SQL INNER JOIN Multiple Tables

In real-world databases, you often need to join more than two tables. You can chain multiple INNER JOINs in a single query. Let us add a Products table and an OrderDetails table to see this in action.

+----+---------+-----------+-----+
| ID | OrderID | ProductID | Qty |
+----+---------+-----------+-----+
| 1  | 1       | 1         | 1   |
| 2  | 1       | 3         | 2   |
| 3  | 2       | 4         | 1   |
| 4  | 4       | 2         | 3   |
+----+---------+-----------+-----+

SELECT c.CustomerName, p.ProductName, od.Qty
FROM Customers AS c
INNER JOIN Orders AS o ON c.ID = o.CustomerID
INNER JOIN OrderDetails AS od ON o.ID = od.OrderID
INNER JOIN Products AS p ON od.ProductID = p.ID;

+----------------+----------------+-----+
| CustomerName   | ProductName    | Qty |
+----------------+----------------+-----+
| Rahul Sharma   | Laptop Pro     | 1   |
| Rahul Sharma   | Wireless Mouse | 2   |
| Sarah Johnson  | Monitor 27"    | 1   |
| Amit Patel     | Desk Lamp      | 3   |
+----------------+----------------+-----+

Each additional INNER JOIN adds another table to the chain. The key is to always match the correct foreign key with its primary key using the ON clause.

You will learn about LEFT JOIN in detail in the next chapter.

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SELECT c.CustomerName, o.Amount, o.OrderDate
FROM Customers AS c
INNER JOIN Orders AS o
ON c.ID = o.CustomerID
WHERE o.Amount > 300;

+----------------+--------+------------+
| CustomerName   | Amount | OrderDate  |
+----------------+--------+------------+
| Sarah Johnson  | 430.00 | 2026-01-18 |
| Amit Patel     | 520.00 | 2026-02-10 |
| Lisa Chen      | 310.00 | 2026-03-05 |
+----------------+--------+------------+

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