Nov 18, 2021 · Here are 5 SQL subquery examples demonstrating how to use scalar, multirow, and correlated subqueries in the WHERE, FROM, JOIN, and SELECT clauses.

Apr 14, 2025 · In this article, we will explain the concept of SQL subqueries, exploring their syntax, use cases, and how they can be applied effectively. We’ll provide detailed examples and outputs to ensure we fully understand how to use subqueries to simplify complex operations.

In this tutorial, you'll learn about SQL subquery, a query nested within another query, to form flexible queries.

Mar 25, 2025 · In this query: The subquery is executed first. It searches the departments table and returns the department_id of the ‘Sales’ department.; Next, the outer query is executed. It retrieves the department_id returned by the subquery and returns all employees whose department_id matches with the retrieved one.; This is how queries, including subqueries, are executed in SQL.

In a subquery, the outer query's result depends on the result set of the inner subquery. That's why subqueries are also called nested queries. Here is how this code works: Suppose we want the details of customers who have placed an order. We can achieve that by using a subquery. FROM Customers . WHERE customer_id IN ( SELECT customer_id.

Dec 12, 2023 · In this article, we present various ways of employing subqueries to create complex queries. We start by introducing SQL subqueries along with common use cases. Then we’ll walk you through 15 SQL subquery practice exercises – complete with solutions and explanations.

The objective of this SQL Server tutorial is to teach you how to use a SUBQUERY in a SQL statement to expand the scope of operation of the statement and to narrow its focus with respect to the output and get more specific output.

Jan 2, 2025 · In this article, We will learn about Subquery in a SELECT statement by understanding various examples and output in detail. A subquery (also known as a nested query or inner query) is a query placed inside another query. The subquery returns a result that is used by the outer query.

May 29, 2020 · In this article, I’ll provide examples of different subquery types in SQL and guide you through the typical scenarios when this kind of subquery is particularly handy. When a subquery returns a single value, or exactly one row and exactly one column, we …

Subqueries are useful when filtering results dynamically based on another query. For example, they can help find employees with salaries above the company average: FROM employees. WHERE salary > (SELECT AVG(salary) FROM employees); When working with multiple tables, a subquery can pre-filter data before joining tables.