A subquery is a query that is nested inside a SELECT , INSERT , UPDATE , or DELETE statement, or inside another subquery. ... A subquery can be used anywhere an expression is allowed. In this example ...

This script demonstrates various subquery techniques in SQL. It covers result types, subqueries in the FROM clause, in SELECT, with comparison operators, IN, ANY, correlated subqueries, and EXISTS.

Sharpen your SQL subquery super‑powers with this hands‑on, self‑contained practice set built around a fictional university. The project ships with an easy‑to‑load PostgreSQL script (Sub_query.sql) ...