AI engineering glossary · SQL databases
What is join?
Join: An operation that combines rows from two or more tables into one result by matching values, usually a foreign key against a primary key. It lets normalised data spread over many tables be read back together.
Join: an example
Joining orders to products on product_id lets a report show the product name next to each order line.
Related terms
More SQL databases terms
- Key-value store
- LAG and LEAD
- LEFT JOIN
- LIMIT and OFFSET
- Locking
- Many-to-many relationship
- Materialized view
- Migration
Where you learn it
Join is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.