'Invalid column name' from within a stored procedure - sql

Question

I wrote a stored procedure to insert future dates (excluding Sat and Sun) into a permanent table. The routine uses just one temp table. The purpose of this post is not to critique the Stored Procedure. Although, I am certain it could be improved. However, the purpose of this post is to analyze why the stored procedure is throwing these errors when called under one set of circumstances and not others.
1 - Here are the errors I receive
Msg 207, Level 16, State 1, Procedure MAKE_FUTURE_DATES, Line 25
Invalid column name 'tdate'.
Msg 207, Level 16, State 1, Procedure MAKE_FUTURE_DATES, Line 31
Invalid column name 'wday'.
2 - Here is the stored procedure
ALTER PROCEDURE [dbo].[MAKE_FUTURE_DATES] (#STARTDATE DATE)
AS
BEGIN
-- We need to populate FUTURE_DATES (table) with forward looking dates (week days only)
-- We do not consider/exclude holidays here. We just exclude Sat/Suns
-- Temp table to hold the dates and days of the week
CREATE TABLE #TMP_DATES(
[tdate] [date] NULL,
[wday] [varchar](10) NULL,
)
-- To generate 'enough' future dates loop up to 1199 days in the future
-- and insert dates that start with the current date and increase with each loop
DECLARE #Loop INT
SET #Loop = 0
WHILE #Loop < 1200
BEGIN
INSERT INTO #TMP_DATES (tdate) VALUES (DATEADD(weekday,#Loop,#STARTDATE))
SET #Loop = #Loop + 1
END
-- Now update the wday column with the weekday name so we can get rid of
-- Sat/Sun in the next step
UPDATE #TMP_DATES
SET wday = UPPER(LEFT(DATENAME(dw,tdate),3))
-- Get rid of Sat/Sun
DELETE FROM #TMP_DATES WHERE wday = 'SAT' or wday = 'SUN'
-- Now clear the final destination table
TRUNCATE TABLE FUTURE_DATES
-- Insert the weekday dates into future_dates
INSERT INTO FUTURE_DATES (fdate,wday)
SELECT tdate,wday FROM #TMP_DATES
DROP TABLE #TMP_DATES
3 - I have been calling the above stored procedure within another stored procedure as a SQL Server task in the background (via the SQL Server job scheduler) for about 6 months without any errors or problems. More recently, I created a new stored procedure, let's call it 'ABC', that calls a stored procedure that calls MAKE_FUTURE_DATEs.
4 - Here is the part I am trying to solve. When ABC is invoked as a SQL Server task in the background (via the SQL Server job scheduler) it throws the errors every time (which is daily) and the results are not produced/it crashes. When I first start up SQL Server Management Studio and run ABC it sometimes throws the error the first time. The second time in this sequence and all subsequent times it does not throw the error. Also, keep in mind that the stored procedure that has been calling MAKE_FUTURE_DATES for 6 months is still quite happy with no errors.
I am looking for suggestions on how to debug this or what to look for. Particularly how can it throw the error sometimes and not others?

Answer 1

The code that you've posted looks fine to me. Is this the complete code?
The only thing that comes to mind is that your "ABC" stored procedure also has a temp table called #TMP_DATES. The temp table in ABC would then also be available in the scope of the called stored procedure.
However, if that were the case, you should get a different error when you called CREATE TABLE #TMP_DATES in the called procedure.

Answer 2

Temp tables have a scope greater than just one procedure.
So you can create a temp table in uspProc1...and if in uspProc1, you call uspProc2, uspProc2 "can see" the temp table you created.
Make sure you provide unique names to your #temp tables.
Below is an example demonstrating the point.
IF EXISTS
(
SELECT * FROM INFORMATION_SCHEMA.ROUTINES
WHERE ROUTINE_TYPE = N'PROCEDURE' and ROUTINE_SCHEMA = N'dbo' and ROUTINE_NAME = N'uspProc001'
)
BEGIN
DROP PROCEDURE [dbo].[uspProc001]
END
GO
CREATE Procedure dbo.uspProc001 (
#Param1 int
)
AS
BEGIN
IF OBJECT_ID('tempdb..#TableOne') IS NOT NULL
begin
drop table #TableOne
end
CREATE TABLE #TableOne
(
SurrogateKey int ,
NameOf varchar(12)
)
Insert into #TableOne ( SurrogateKey , NameOf ) select 1001, 'uspProc001'
Select * from #TableOne
EXEC dbo.uspProc002
Select * from #TableOne
IF OBJECT_ID('tempdb..#TableOne') IS NOT NULL
begin
drop table #TableOne
end
END
GO
IF EXISTS
(
SELECT * FROM INFORMATION_SCHEMA.ROUTINES
WHERE ROUTINE_TYPE = N'PROCEDURE' and ROUTINE_SCHEMA = N'dbo' and ROUTINE_NAME = N'uspProc002'
)
BEGIN
DROP PROCEDURE [dbo].[uspProc002]
END
GO
CREATE Procedure dbo.uspProc002
AS
BEGIN
IF OBJECT_ID('tempdb..#TableOne') IS NOT NULL
begin
Insert into #TableOne ( SurrogateKey , NameOf ) select 2001, 'uspProc002'
end
END
GO
exec dbo.uspProc001 0