SQL Server stored procedure running in infinite loop - sql

Question

I am running a stored procedure which is running infinitely.
I have used a while loop that seems to be running without ever ending.
CREATE PROCEDURE ABC
AS
BEGIN
SET NOCOUNT ON;
DECLARE #Id INT;
DECLARE #iter INT = 1;
DECLARE #iterMax INT;
DECLARE #psubject VARCHAR(100);
DECLARE #pbody NVARCHAR(MAX);
DECLARE #pSendTo NVARCHAR(MAX);
DECLARE #pProfile VARCHAR(MAX);
IF OBJECT_ID('tempdB..#temp') IS NOT NULL
DROP TABLE #temp;
SET #pProfile = 'Test';
IF ((SELECT COUNT(*)
FROM [Table_A] R
JOIN [Table_B] T ON R.Id = T.r_Id
WHERE R.[Date] <= (DATEADD(DAY, -1, GETDATE()))
AND T.[Sent_Flag] IS NULL) >= 1)
BEGIN
SELECT IDENTITY(int, 1, 1) AS RecId,
[r_id] * 1 AS Id
INTO #temp
FROM [Table_A] R
JOIN [Table_B] T ON R.Id = T.r_Id
WHERE R.[Date] <= (DATEADD(DAY, -1, GETDATE()))
AND T.[Sent_Flag] IS NULL;
BEGIN
SET #iterMax = (SELECT COUNT(*)FROM #temp);
WHILE (#iter <= #iterMax)
BEGIN
SET #psubject = 'HIIII'; /*this is in HTML example */
SET #pbody = 'You got one email';
IF ((SELECT COUNT(*)
FROM [Table_B]
WHERE R_Id = (SELECT Id FROM #temp WHERE RecId = #iter)
AND [Mail1_Flag] = 'Y'
AND [Mail2_Flag] = 'Y') = 1)
BEGIN
IF ((SELECT COUNT(*)
FROM [Table_A] R
JOIN [Table_B] T ON R.Id = T.r_Id
WHERE R_Id = (SELECT Id FROM #temp WHERE RecId = #iter)
AND R.[Date] <= (DATEADD(DAY, -1, GETDATE()))
AND T.[Sent_Flag] IS NULL) = 1)
BEGIN
SET #pSendTo = N'ABC#gmail.com';
EXEC msdb.dbo.sp_send_dbmail #profile_name = #pProfile,
#body = #pbody,
#subject = #psubject,
#recipients = #pSendTo,
#body_format = 'HTML';
END;
UPDATE [Table_B]
SET [Sent_Flag] = 'Y'
WHERE [Id] IN (SELECT Id FROM #temp WHERE RecId = #iter);
END;
END;
SET #iter = #iter + 1;
END;
END;
IF OBJECT_ID('tempd..#temp') IS NOT NULL
DROP TABLE #temp;
END;
This program is checking that if date is more than 24 hours then it will send a mail correspondingly. I am able to trigger a mail. But I am getting multiple mails. Like the loop is running infinitely and getting same mail multiple times and the sent_Flag column is initial NULL and after a mail is sent it sholud update to 'Y' but it is also not updating to 'Y' after mail is triggered.
Please help to resolve this issue. Thank you

Answer 1

You are not incrementing the counter inside the loop:
UPDATE [Table_B]
SET [Sent_Flag] = 'Y'
WHERE [Id] IN (SELECT Id FROM #temp WHERE RecId = #iter);
END; --this is the END of the first IF BEGIN
END; --this is the END of the WHILE BEGIN
SET #iter = #iter + 1; --and here you update the counter, which will never be reached
If you don't increment the counter inside the loop, the loop will run infinitely, since the loop condition will always be true.