Answer
A subquery is a query nested inside another SQL statement. • It can produce a scalar value, a row, or a table-like result depending on context. • It may appear in expressions, FROM, WHERE, or other supported clauses. • The database optimizer may transform its execution.
💡 SQL Example
SELECT name FROM employees WHERE salary > (SELECT AVG(salary) FROM employees);
Result
Employees earning above the average
⚡ Quick Revision
A subquery supplies a query result to another statement.