joining a varchar with a int column

just noticed this, wonder if there is a performance hit
got results when executing the following
select AgendaID
from ObjectiveAgenda
Inner Join Objective On Objective.ObjectiveID =
ObjectiveAgenda.ObjectiveID
problem is that the ObjectiveID column in one table is of SQL type
INTEGER, while in the other table is of type VARCHAR.
wonder if it is doing a translation behind the scenes, with some
performance hit.Yes, SQL Server will have to convert the value and this can cause table scan
.
Thus this can cause major negative impact.
Here is a script I have used for testing. In the Query Analyser, please
'Display Execution Plan' for the 2 queries at the end of my script. One will
cause Table Scan and another will go for Index S.
set nocount on
create table #test111
(scode int,
sdesc varchar(30))
create index idx1_test111
on #test111(sdesc)
declare @.val1 int
set @.val1 = 1
while @.val1 < 10000
begin
insert into #test111
values(@.val1, convert(varchar(30),(@.val1 * @.val1)))
set @.val1 = @.val1 + 1
end
select * from #test111 where sdesc = 25
go
select * from #test111 where sdesc = '25'
"arzewski@.hotmail.com" wrote:

> just noticed this, wonder if there is a performance hit
> got results when executing the following
> select AgendaID
> from ObjectiveAgenda
> Inner Join Objective On Objective.ObjectiveID =
> ObjectiveAgenda.ObjectiveID
> problem is that the ObjectiveID column in one table is of SQL type
> INTEGER, while in the other table is of type VARCHAR.
> wonder if it is doing a translation behind the scenes, with some
> performance hit.
>