# Types of Sub-Queries

The difference between an uncorrelated sub-query, which runs once on its own, and a correlated sub-query, which runs once for each row of the outer query.

![Cheat sheet: Types of Sub-Queries](https://fsdtrainingmedia.blob.core.windows.net/public/images/2026/11/61611063c24e446ba17cebee17b12524.webp)

- Category: SQL
- Level: Journeyman
- Tags: mysql, sql
- Updated: November 3, 2026

Source: https://www.ask-codey.com/cheat-sheets/working-with-sub-queries-types-of-sub-queries-cheat-sheet