In MySQL, an inner join is used to combine rows from two or more tables based on a related column between them. An inner join returns only the rows where there is a match in both tables based on the specified join condition. The basic syntax for an inner join in MySQL is:
SELECT columns FROM table1 INNER JOIN table2 ON table1.column = table2.column;
In this syntax, columns are the columns you want to select from the combined tables, table1 is the first table, table2 is the second table you want to join, and column is the related column between the two tables.
Here’s an example of an inner join between two tables:
SELECT orders.order_id, customers.customer_name FROM orders INNER JOIN customers ON orders.customer_id = customers.customer_id;
In this example, the orders table and the customers table are joined using the customer_id column, and only the records with matching customer IDs in both tables will be returned.
For example, consider two tables, employees and departments, where the departments table has a column dept_id that relates to the employees table’s column dept_id. We can use an inner join to get all the employees and their corresponding department names.
SELECT employees.employee_name, departments.department_name FROM employees INNER JOIN departments ON employees.dept_id = departments.dept_id;
In this example, the employees table and the departments table are joined using the dept_id column, and only the records with matching department IDs in both tables will be returned, along with their corresponding employee and department names.
