If Nothing Selected Into Variable What Is The Value Of Variable?

DECLARE @.PayTypeValue numeric (18, 5)
SET @.PayTypeValue = (SELECT [LoadPayValue] FROM [CSITSS].[dbo].[LoadPayType] WHERE [CompanyDiv] = @.CompDiv AND [Deleted] = 0 AND [LoadPayType] = @.LoadPay)
IF THIS QUERY RETURNS NOTHING WHAT DOES IT SET @.PayTypeValue to?
NULL OR 0DECLARE @.PayTypeValue numeric (18, 5)

SET @.PayTypeValue = (SELECT [LoadPayValue] FROM [CSITSS].[dbo].[LoadPayType] WHERE [CompanyDiv] = @.CompDiv AND [Deleted] = 0 AND [LoadPayType] = @.LoadPay)

IF THIS QUERY RETURNS NOTHING WHAT DOES IT SET @.PayTypeValue to?

NULL OR 0

why don't you try it and see for yourself:

SELECT @.PayTypeValue= [LoadPayValue] FROM [CSITSS].[dbo].[LoadPayType] WHERE 1=0
select @.PayTypeValue|||Also, try
SET @.PayTypeValue = 42
SELECT @.PayTypeValue= [LoadPayValue] FROM [CSITSS].[dbo].[LoadPayType] WHERE 1=0
select @.PayTypeValue

and see what happens.|||i thought it would return NULL.....|||But it returns...

The answer would be useful for people with similar questions ;)|||The answer is 42.
If the query returns no rows, the variable keeps its old value.|||Ahh that's clever - kinda like having an "else" value.
Cheers ivon|||hmmm...

That could be dangerous if you were using that variable in a loop.
I would wrap the SQL in ISNULL()

set @.somevariable=ISNULL((select somevalue from sometable),-9999999)
If @.somevariable=-9999999
'no rows were returned
Else|||That could be dangerous if you were using that variable in a loop.

How so? It retained it's initially declared value...
If you looped round, @.PayTypeValue would equal 42 each time..?|||Yes, but if you were expecting the value to change with each iteration...
What is returned from the select statement is also dependant on
@.compdiv and @.loadpay, so if those values change, it's quite possilbe that @.paytypevalue would change, too.|||Yes, but if you were expecting the value to change with each iteration...
That's how I found out; I got some very peculiar results.

BTW using IsNull() won't help: the query returns no rows, so there is no null value to replace with something else.

Solutions I'm using are
- Setting the variable to a default value before filling it with the query,
- Checking @.@.ROWCOUNT to see if any rows were returned from the query.|||I think it all depends on how you put it together.

declare @.tmp integer
set @.tmp=42
set @.tmp=isnull((select 18 where 1=0),0)
select @.tmp

Returns 0, which is what I'd expect, since
SELECT 18 WHERE 1=0
returns no rows|||How do I use @.@.ROWCOUNT to do this?

I haven't set this variable to anything before this and at least this instance doesn't loop. This SP is called once per order and checks 14 different things. Then feeds the results into a verification table. Those results and then selected by Crystal Reports and displayed to the user for an entire batch of orders one at a time by order number.|||RedNeckGeek: I now see that you put the isnull around the entire query.

tdecker81:
Something like
SELECT @.l_var = value
FROM table
WHERE <conditions>

SELECT @.l_records = @.@.ROWCOUNT

IF @.l_records > 0
BEGIN
' Do stuff with @.l_var
END|||Interesting. Since I rarely use the first syntax, I was unaware of this behavior:
set nocount on

declare @.MyValue int
set @.MyValue = 42

--This method retains @.MyValue
select @.MyValue = id from sysobjects where 1 = 0
select @.MyValue as 'Unchanged!'

--This method sets @.MyValue to NULL
set @.MyValue = (select id from sysobjects where 1 = 0)
select @.MyValue as 'Set to NULL!'

Learn something new every day...|||Learn something new every day...

my problem is I forget 2 somethings every day, so I think I'm losing the battle...

(most of it is stuff my wife tells me so I guess it's ok)

:)|||I'm sure you're wife will be there to constantly remind you too.sql