What is a subquery in SQL, and how is it different from a join?
adminnewd Changed status to publish September 19, 2024
A subquery is a query nested inside another query. It is used to perform operations that require multiple steps or to filter results based on the results of another query. Subqueries can be used in various SQL clauses like SELECT
, WHERE
, FROM
, and HAVING
.
Difference from a Join:
- Subquery: A subquery runs once for the parent query, and its results are used in the parent query. It can be used when you need to filter or compute results based on the output of another query.
- Join: A join combines rows from two or more tables based on a related column between them. It is used to retrieve related data from multiple tables in a single query.
anonymous Answered question September 19, 2024