Question

I have the following data:

I would like to express the FTSEAllShare in terms of all its primitives (ie. Corp1, Corp2, Corp3, Corp4).
I’ve written a WHILE loop that repeatedly SELF JOINs MemberName to GroupName and COALESCEs the resulting MemberName, but I’ve been reading about recursive CTEs and thought that they may offer a simpler way of doing it.

I’m not good with recursive code and I find myself getting confused everytime I try.

Could someone please help me out with this and suggest how I may use a recursive CTE to express the FTSEAllShare in terms of its 4 primitives?

Kind regards

Answer 1

Like this:

WITH CTE
AS
(
  SELECT GroupName, MemberName, 0 AS Level
  FROM GroupsMembers 
  WHERE GroupName = 'FRSEAllShare'
  UNION ALL
  SELECT g.*, c.level + 1
  FROM CTE c
  INNER JOIN GroupsMembers g ON c.MemberName = g.GroupName
)
SELECT * 
FROM CTE;

Live Demo

This will give you all the members that belongs to the group FRSEAllShare, or any of its grandchilds groups, with a new column level to select them by level.