Maintaining Variable After EXEC

[Chip Mayan]

Hello,

I am fairly new at stored procedures. I have created some that will
go through a table and return a start date and an end date that is
dependent upon the fiscal period you want, but I then need to use
those dates in another stored procedure to retrieve the information I
need. My stored procedure looks like this.

=============== =============== =============== =============== ==========

CREATE PROCEDURE dbo.R920ExtTota l
@MthsBack Decimal OUTPUT
AS

DECLARE @sSQL AS NVARCHAR(255), @StartDate as SMALLDATETIME, @EndDate
as SMALLDATETIME

Exec @StartDate = GetMthStart @MthsBack

Exec @EndDate = GetMthEnd @MthsBack

SET @sSQL = 'Select count(extension ) as Total From r920f00 Where
([date] BETWEEN "' +
CONVERT(nvarcha r, @StartDate) +
'" and "' +
CONVERT(nvarcha r, @EndDate) +
'")'

Select @sSQL

EXEC (@sSQL)

Return
GO

=============== =============== =============== =============== =====

The problem is my variables @StartDate and @EndDate do not retain
their values after the EXEC statement and revert to 01/01/1900. How
can I get around this problem?

Thanks!!!!

Chip

[Steve Jorgensen]

Re: Maintaining Variable After EXEC

Variables are only available in the scope within which they are declared. If
you need to move values out of a stored procedure, you must use output
parameters for all of them. Also, why are you building dynamic SQL in your
procedure? You can use the variables directly in SQL queries - there is no
need to convert them to strings, and insert them into a SQL string.

On 6 Jan 2004 11:05:01 -0800, cmayan@leslieco ntrols.com (Chip Mayan) wrote:
[color=blue]
>Hello,
>
>I am fairly new at stored procedures. I have created some that will
>go through a table and return a start date and an end date that is
>dependent upon the fiscal period you want, but I then need to use
>those dates in another stored procedure to retrieve the information I
>need. My stored procedure looks like this.
>
>============== =============== =============== =============== ===========
>
>CREATE PROCEDURE dbo.R920ExtTota l
>@MthsBack Decimal OUTPUT
>AS
>
>DECLARE @sSQL AS NVARCHAR(255), @StartDate as SMALLDATETIME, @EndDate
>as SMALLDATETIME
>
>Exec @StartDate = GetMthStart @MthsBack
>
>Exec @EndDate = GetMthEnd @MthsBack
>
>SET @sSQL = 'Select count(extension ) as Total From r920f00 Where
>([date] BETWEEN "' +
> CONVERT(nvarcha r, @StartDate) +
> '" and "' +
> CONVERT(nvarcha r, @EndDate) +
> '")'
>
>Select @sSQL
>
>EXEC (@sSQL)
>
>Return
>GO
>
>============== =============== =============== =============== ======
>
>The problem is my variables @StartDate and @EndDate do not retain
>their values after the EXEC statement and revert to 01/01/1900. How
>can I get around this problem?
>
>Thanks!!!!
>
>Chip[/color]

[Erland Sommarskog]

Re: Maintaining Variable After EXEC

Chip Mayan (cmayan@lesliec ontrols.com) writes:[color=blue]
> I am fairly new at stored procedures. I have created some that will
> go through a table and return a start date and an end date that is
> dependent upon the fiscal period you want, but I then need to use
> those dates in another stored procedure to retrieve the information I
> need. My stored procedure looks like this.
>
>============== =============== =============== =============== ===========
>
> CREATE PROCEDURE dbo.R920ExtTota l
> @MthsBack Decimal OUTPUT
> AS
>
> DECLARE @sSQL AS NVARCHAR(255), @StartDate as SMALLDATETIME, @EndDate
> as SMALLDATETIME
>
> Exec @StartDate = GetMthStart @MthsBack
>
> Exec @EndDate = GetMthEnd @MthsBack
>
> SET @sSQL = 'Select count(extension ) as Total From r920f00 Where
> ([date] BETWEEN "' +
> CONVERT(nvarcha r, @StartDate) +
> '" and "' +
> CONVERT(nvarcha r, @EndDate) +
> '")'
>
> Select @sSQL
>
> EXEC (@sSQL)
>
> Return
> GO[/color]

I'm afraid that there are a couple of errors or strange things in this
procedure.

First: there is absolutely no reason to use dynamic SQL here. Just write:

SELKCT count(extension ) AS Total
FROM r920f00
WHERE [date] BETWEEN @StartDate AND @EndDate

Second: the calls to set @StartDate and @EndDate looks funny. If
GetMthStart and GetMthEnd are user-defined functions it would be alright,
but you indicated that they were stored procedures. The return value from
a stored procedure is always an integer value, so you cannot return a
date here. And I would strongly recommend you to use return values solely
for indication of success/failure (with 0 meaning success, and about
everything else meaning failure.) So you would have to make the output
parameters:

EXEC GetMthStart @MthsBack, @StartDate OUTPUT

Third: the @MthsBack parameter is declared as output, but you never assign
it any value, you only seem to use it for input.

--
Erland Sommarskog, SQL Server MVP, sommar@algonet. se

Books Online for SQL Server SP3 at

http://www.microsoft.com/sql/techinfo/productdoc/2000/books.asp