# Theta Join

A join defined by an arbitrary comparison predicate between its inputs.

## What is **Theta Join** in a relational database?

**Theta Join** — A join defined by an arbitrary comparison predicate between its inputs.

Level: Master · [More Database terms at this level](https://www.ask-codey.com/glossary/subjects/database/master)

Updated: September 27, 2026

Source: https://www.ask-codey.com/glossary/theta-join