# Nested Subqueries A subquery is a select-from-where query that is nested within another query. A common use of subqueries is to perform tests for set membership (in/not in), set comparisons and set cardinality. Ex. to get the names of instructors who get a salary greater than that of at least one instructor in the Biology department: ``` select name from instructor where salary > some (select salary from instructor where dept_name='Biology') ``` Ex. to get the names of instructors who get a salary greater than that of all the instructors in the Biology department: ``` select name from instructor where salary > all (select salary from instructor where dept_name='Biology') ``` --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://vikram-bajaj.gitbook.io/cs-gy-6083-principles-of-database-systems/main-1/sql/dml-commands/nested-subqueries.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.