C. Multi-statement table-valued function
Given a table that represents a hierarchical relationship: 

CREATE TABLE employees (empid nchar(5) PRIMARY KEY, 
      empname nvarchar(50), 
      mgrid nchar(5) REFERENCES employees(empid), 
      title nvarchar(30)
      )

The table-valued function fn_FindReports(InEmpID), which -- given an Employee ID -- returns a table corresponding to all the employees that report to the given employee directly or indirectly. This logic is not expressible in a single query and is a good candidate for implementing as a user-defined function. 

CREATE FUNCTION fn_FindReports (@InEmpId nchar(5))
RETURNS @retFindReports TABLE (empid nchar(5) primary key,
   empname nvarchar(50) NOT NULL,
   mgrid nchar(5),
   title nvarchar(30))
/*Returns a result set that lists all the employees who report to given 
employee directly or indirectly.*/
AS
BEGIN
   DECLARE @RowsAdded int
   -- table variable to hold accumulated results
   DECLARE @reports TABLE (empid nchar(5) primary key, 
      empname nvarchar(50) NOT NULL,
      mgrid nchar(5),
      title nvarchar(30),
      processed tinyint default 0)
-- initialize @Reports with direct reports of the given employee 
   INSERT @reports
   SELECT empid, empname, mgrid, title, 0
   FROM employees 
   WHERE empid = @InEmpId 
   SET @RowsAdded = @@rowcount
   -- While new employees were added in the previous iteration
   WHILE @RowsAdded > 0
   BEGIN
      /*Mark all employee records whose direct reports are going to be 
   found in this iteration with processed=1.*/
      UPDATE @reports
      SET processed = 1
      WHERE processed = 0
      -- Insert employees who report to employees marked 1.
      INSERT @reports
      SELECT e.empid, e.empname, e.mgrid, e.title, 0
      FROM employees e, @reports r
      WHERE e.mgrid=r.empid and e.mgrid <> e.empid and r.processed = 1
      SET @RowsAdded = @@rowcount
      /*Mark all employee records whose direct reports have been found
   in this iteration.*/
      UPDATE @reports
      SET processed = 2
      WHERE processed = 1
   END
   
   -- copy to the result of the function the required columns
   INSERT @retFindReports
   SELECT empid, empname, mgrid, title 
   FROM @reports
   RETURN
END
GO

-- Example invocation
SELECT * 
FROM fn_FindReports('11234')
GO

quote:

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Originally posted by kselvia

Or take a look at this article: http://www.sqlteam.com/item.asp?ItemID=2652

--Ken

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