Question : SQL 2005 Nested Stored Procedure, how to return a value to a trigger

I am trying to write a stored procedure that I can call from a trigger that will return a comma separated ID list of the parent and it's children. This is what I have for the stored procedure:

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CREATE PROCEDURE dbo.ShowHierarchy
(
	@Root int,
    @idList varchar(100) OUTPUT
)
AS
BEGIN
	SET NOCOUNT ON
	DECLARE @IndID int, @IndName varchar(30)

	SET @IndName = (SELECT ID FROM dbo.forum_industries WHERE ID = @Root)
	PRINT REPLICATE('-', @@NESTLEVEL * 4) + @IndName
    
    SET @idList = @idList + ',' + CAST(@IndName AS VARCHAR(100))

	SET @IndID = (SELECT MIN(ID) FROM dbo.forum_industries WHERE ParentID = @Root)

	WHILE @IndID IS NOT NULL
	BEGIN

        EXEC dbo.ShowHierarchy @IndID, @idList--, @finalIdList
		SET @IndID = (SELECT MIN(ID) FROM dbo.forum_industries WHERE ParentID = @Root AND ID > @IndID)
           
    END
	
END

When I call this, I do get in the message the right ID's displayed. By the way, the @IndName is actually the ID and I will name it better once I get this working.

In my Trigger I am not sure how to call it and get the value back. My trigger code

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BEGIN
    DECLARE @IndID int
    DECLARE @idList varchar

	-- Find out whether we check the inserted or deleted table, depending on whether a record is getting deleted or inserted or updated.
	if (select count(*) from inserted) <> 0 and (select count(*) from deleted) = 0 --insert
	begin
		SELECT @IndID = forum_industriesID FROM inserted
	end
	if (select count(*) from inserted) <> 0 and (select count(*) from deleted) <> 0 --update
	begin
		SELECT @IndID = forum_industriesID FROM inserted
	end
	if (select count(*) from inserted) = 0 and (select count(*) from deleted) <> 0 --delete
	begin
		SELECT @IndID = forum_industriesID FROM deleted
	end
    
        
    SET @idList = 0
    EXECUTE ShowHierarchy @IndID, @idList
  -- Query code to store the IDList or select based on the list
END

So, my hope is that my trigger will call this ShowHIerarchy and pass in the root, and return a value like 5,6,7,10,50,100 and I can use that in a query like: select count(id) from table where forum_industriesID IN (@idList)

The code I have so far returns nothing, so I don't know how to get the values back out.

I am fairly new to writing stored procedures and triggers and so any suggestions would be most helpful.

Answer : SQL 2005 Nested Stored Procedure, how to return a value to a trigger

change DECLARE @idList varchar

to DECLARE @idList varchar(100) -- to be a proper type

then on the end of your
triget do it like thi :

SET @idList = ''
EXECUTE ShowHierarchy @IndID, @idList output
-- Query code to store the IDList or select based on the list

and then dynamic sql

declare @sqlStatement varchar(4000)
set @sqlStatement = 'select count(id) from table where forum_industriesID IN (' + @idList +')'

EXEC(@sqlStatement )