What is a Subquery in SQL?

Data Analyst - Interview Questions

A Subquery in SQL is a query within another query. It is also known as a nested query or an inner query. Subqueries are used to enhance the data to be queried by the main query.

It is of two types : Correlated and Non-Correlated Query.

Below is an example of a subquery that returns the name, email id, and phone number of an employee from Texas city.

SELECT name, email, phone

FROM employee

WHERE emp_id IN (

SELECT emp_id

FROM employee

WHERE city = 'Texas');?