SQL INNER JOIN

The INNER JOIN keyword selects records that have matching values in both tables.

Syntax

SELECT columns
FROM table1
INNER JOIN table2
ON table1.common_column = table2.common_column;

Example: INNER JOIN

SELECT employees.name, departments.department_name
FROM employees
INNER JOIN departments
ON employees.department_id = departments.id;

Sample Tables

Consider the following two tables:

Employees Table

| id | name        | department_id |
|----|-------------|---------------|
| 1  | John Doe    | 1             |
| 2  | Jane Smith  | 2             |
| 3  | Mike Johnson| 1             |
| 4  | Emily Davis | 3             |

Departments Table

| id | department_name |
|----|-----------------|
| 1  | HR              |
| 2  | Sales           |
| 3  | IT              |
| 4  | Marketing       |

Result of INNER JOIN

| name        | department_name |
|-------------|-----------------|
| John Doe    | HR              |
| Mike Johnson| HR              |
| Jane Smith  | Sales           |
| Emily Davis | IT              |

Only employees with a matching department_id in the departments table are returned.