Hierarchical and recursive queries in SQL

Hierarchical and recursive queries in SQL are techniques used to query data that involves hierarchical relationships between records. These types of queries are particularly useful when working with data that has a parent-child relationship, such as organizational structures, category trees, or bill of materials. ### Hierarchical Queries Hierarchical queries are used to retrieve data in a hierarchical format from a database. These are common in databases that support hierarchical data, such as Oracle.