Subquery

A Subquery is like a question within a question that helps you get more specific information from a database. In business intelligence and data analytics, a subquery lets you use the result of one query as the input for another. Imagine you’re at a bookstore looking for a mystery novel. You first ask the clerk to find all mystery books (that’s your main query). Then, from that selection, you ask for books written by a specific author (that’s your subquery).

In practice, a business might want to find out which customers made the biggest purchases last year. A subquery can help by first finding all purchases from last year, then, within that list, identifying the customers who spent the most. It’s a focused approach that allows for more complex data retrieval, giving businesses precise answers to detailed questions.

Subqueries are powerful tools for dissecting data in layers, allowing analysts to drill down into the nitty-gritty details that can lead to meaningful insights. They help businesses comb through their data more efficiently and answer multi-part questions with greater ease, leading to more informed decision-making strategies.