Contents
How to define a recursive common table expression?
The following guidelines apply to defining a recursive common table expression: The recursive CTE definition must contain at least two CTE query definitions, an anchor member and a recursive member.
How to limit the number of recursion in limitedloop?
WITH LimitedLoop AS ( SELECT 0 AS RecursionLevel UNION ALL SELECT (LimitedLoop.RecursionLevel + 1) AS RecursionLevel FROM LimitedLoop WHERE (LimitedLoop.RecursionLevel + 1) <= 50 ) SELECT * FROM LimitedLoop This query is manually limited to 200 levels of recursion.
How to limit CTE recursion to rows just?
[Level]+1 FROM tblNodes AS t1 INNER JOIN CTE AS t2 ON t1.ParentNodeID = t2.ChildNodeID ) SELECT t1.ChildNodeID, t2.ChildNodeID, t1. [Level]- t2. [Level] AS GenerationsDiff FROM CTE AS t1 CROSS APPLY CTE t2 This will return the generation difference between all nodes, you can modify it for you exact needs.
Is there a default recursion limit in SQL Server?
The issue is with the Sql Server default recursion limit (100). If you try your example at the top with the anchor restriction removed (also added Order By):
Can a common table expression include references to itself?
A common table expression that includes references to itself (a recursive common table expression) is not supported. Specifying more than one WITH clause in a CTE is not allowed. For example, if a CTE query definition contains a subquery, that subquery cannot contain a nested WITH clause that defines another CTE.
How to use common table expression in SQL?
The number of columns in the anchor and recursive members must be the same. The data type of a column in the recursive member must be the same as the data type of the corresponding column in the anchor member. The FROM clause of a recursive member must refer only one time to the CTE expression_name.
What are the parts of a recursive CTE in SQL?
Code language: SQL (Structured Query Language) (sql) In general, a recursive CTE has three parts: An initial query that returns the base result set of the CTE. The initial query is called an anchor member. A recursive query that references the common table expression, therefore, it is called the recursive member.