Описание тега recursive-query
The ability to run recursive queries in SQL
Recursive SQL queries offer the ability to retrieve hierarchical information in a relational database (e.g. "adjacency list model"). The SQL standard defines recursive common table expressions (CTE) for this purpose. Some vendors such as Oracle have implemented this functionality with a proprietary syntax (CONNECT BY). Recursive CTEs are supported by a wide range of DBMS such as Oracle, SQL Server, DB2, PostgreSQL, Firebird SQL, Teradata and others.