Stored procedure inserting the same record repeatedly instead of looping through list from SELECT - sql-server

Question

I am fairly new at writing procedures (beyond the basics)
I am trying to write a stored procedure that inserts into a table (dbo.billing_batch) based on a select statement that loops through the list of results (#DealerID FROM dbo.vehicle_info).
The SELECT DISTINCT... statement on its own works perfectly and returns a list of 54 records.
The result of the SELECT statement is dynamic and will change from week to week, so I cannot count on 54 records each time.
I am trying to use WHILE #DealerID IS NOT NULL to loop through the INSERT routine.
The loop is supposed to update dbo.billing_batch, however it is inserting the same 1st record (BillingBatchRosterID, DealerID) over and over and over to infinity.
I know I must be doing something wrong (I have never written a stored procedure that loops).
Any help would be greatly appreciated!
Here is the stored procedure code:
ALTER PROCEDURE [dbo].[sp_billing_batch_set]
#varBillingBatchRosterID int
AS
SET NOCOUNT ON;
BEGIN
DECLARE #DealerID int
SELECT DISTINCT #DealerID = vi.DealerID
FROM dbo.vehicle_info vi
LEFT JOIN dbo.dealer_info di ON di.DealerID = vi.DealerID
WHERE di.DealerActive = 1
AND (vi.ItemStatusID < 4 OR vi.ItemStatusID = 5 OR vi.ItemStatusID = 8)
END
WHILE #DealerID IS NOT NULL
BEGIN TRY
INSERT INTO dbo.billing_batch (BillingBatchRosterID, DealerID)
VALUES(#varBillingBatchRosterID, -- BillingBatchRosterID - int
#DealerID) -- DealerID - int
END TRY
BEGIN CATCH
SELECT ' There was an error: ' + error_message() AS ErrorDescription
END CATCH

Answer 1

You have the same problems as another recent post here: Iterate over a table with a non-int id value
Why do a loop? Just do it as a single SQL statement
If you must use a loop, you will need to update your #Dealer value at each run (e.g., to the next DealerId) otherwise it will just infinitely loop with the same DealerID value
Don't do a loop.
Here's an example not needing a loop.
ALTER PROCEDURE [dbo].[P_billing_batch_set]
#varBillingBatchRosterID int
AS
BEGIN
SET NOCOUNT ON;
BEGIN TRY
INSERT INTO dbo.billing_batch (DealerID, BillingBatchRosterID)
SELECT DISTINCT vi.DealerID, #varBillingBatchRosterID
FROM dbo.vehicle_info vi
INNER JOIN dbo.dealer_info di ON di.DealerID = vi.DealerID
WHERE di.DealerActive = 1
AND (vi.ItemStatusID < 4
OR vi.ItemStatusID = 5
OR vi.ItemStatusID = 8
);
END TRY
BEGIN CATCH
SELECT ' There was an error: ' + error_message() AS ErrorDescription;
END CATCH;
END;
Note I
Changed the LEFT JOIN to an INNER JOIN as your WHERE clause needs the record to exist in the dealer_info table
Moved the SET NOCOUNT ON; to be within the BEGIN-END section
Moved the END to the end
Renamed your stored procedure as per the excellent comment from #marc_s (on the question itself)