A recursive query is one that refers to itself. … Different DBMS products implement recursive SQL in different ways. Recursion is implemented in standard SQL-99 using common table expressions (CTEs). DB2, Microsoft SQL Server, Oracle and PostgreSQL all support recursive queries using CTEs.

What is recursive query in SQL example?

A recursive query is one that is defined by a Union All with an initialization fullselect that seeds the recursion. The iterative fullselect contains a direct reference to itself in the FROM clause. There are additional restrictions as to what can be specified in the definition of a recursive query.

What is recursive SQL Server?

Introduction to SQL Server recursive CTE A recursive common table expression (CTE) is a CTE that references itself. By doing so, the CTE repeatedly executes, returns subsets of data, until it returns the complete result set. … An initial query that returns the base result set of the CTE.