Subqueries in SQL

 Subqueries in SQL

A subquery is a query within another query. We can use subqueries to retrieve data from one table based on the values of another table. Here's an example:

sql

SELECT name, department

FROM employees

WHERE department IN (

    SELECT id

    FROM departments

    WHERE name = 'Sales'

);

In this example, we're selecting the name and department of employees who work in the Sales department. We're using a subquery to retrieve the department id of the Sales department from the "departments" table and then filtering the "employees" table based on that id.