Subqueries are SQL queries embedded within another query, used to isolate specific rows for various operations. They are applicable in different business cases and scenarios for joining data. Subqueries can be utilized with SELECT, UPDATE, INSERT, and DELETE statements. SQL supports several types of subqueries, including single-row, multiple-row, multiple-column, correlated, and nested subqueries.
Types of Subqueries in SQL
- Single Row Subquery
- Multiple Row Subquery
- Multiple Column Subqueries
- Correlated Subqueries
- Nested Subqueries