Subquery

Definitions

1. A SQL query nested inside another query, typically within a WHERE, FROM, or SELECT clause. The inner query executes first and its result is used by the outer query — for example, finding all orders whose total exceeds the average: `WHERE total > (SELECT AVG(total) FROM orders)`.

   In plain English: A query inside another query, where the inner one calculates a result that the outer one uses as part of its own filter or data source.

   Example: "The subquery pulls the latest price per SKU, then the outer query joins it to the order lines."

Related Terms

• index
• stored procedure
• trigger
• foreign key
• Join
• Outer Join
• Right Join
• MariaDB
• CockroachDB
• Composite Index