query by grouping

Hi,
I have a table with data that every 2 rows have same data for most of
cloumns (11), only 4 columns have different data. I would like to query this
table so that such rows appear as single row in the result ( I don't need th
e
4 cloumns), so I used that 11 columns in my group by clause.
A large group by will be perforance problem?
ThanksGroup by and Distinct do the same thing (well, not really - ones for
aggrigating - but anyway), and using distinct will make your code a little
cleaner, rather than having a group by statement with 11 columns in it, you
can just use the word distinct to return all rows without duplicates.
Simon Worth
"Jen" <Jen@.discussions.microsoft.com> wrote in message
news:8167FA52-468D-48BC-8D35-8F0E7BD69E46@.microsoft.com...
> Hi,
> I have a table with data that every 2 rows have same data for most of
> cloumns (11), only 4 columns have different data. I would like to query
this
> table so that such rows appear as single row in the result ( I don't need
the
> 4 cloumns), so I used that 11 columns in my group by clause.
> A large group by will be perforance problem?
> Thanks|||If you don't need the 4 columns that have different values, just leave them
out of the query, and add the word Distinct immediatey after the Select
Select Distinct ....
That will do the trick...
"Jen" wrote:

> Hi,
> I have a table with data that every 2 rows have same data for most of
> cloumns (11), only 4 columns have different data. I would like to query th
is
> table so that such rows appear as single row in the result ( I don't need
the
> 4 cloumns), so I used that 11 columns in my group by clause.
> A large group by will be perforance problem?
> Thanks|||Hi,
How about when i use the word SUM, do i have to put all the columns in the
group by?
Thanks,
Bruno N
"Jen" <Jen@.discussions.microsoft.com> escreveu na mensagem
news:8167FA52-468D-48BC-8D35-8F0E7BD69E46@.microsoft.com...
> Hi,
> I have a table with data that every 2 rows have same data for most of
> cloumns (11), only 4 columns have different data. I would like to query
this
> table so that such rows appear as single row in the result ( I don't need
the
> 4 cloumns), so I used that 11 columns in my group by clause.
> A large group by will be perforance problem?
> Thanks|||If you are aggrigating, yes, you would use group by instead of distinct.
Simon Worth
"Bruno N" <nylren@.hotmail.com> wrote in message
news:eB$VmrOJFHA.3596@.TK2MSFTNGP14.phx.gbl...
> Hi,
> How about when i use the word SUM, do i have to put all the columns in the
> group by?
> Thanks,
> Bruno N
> "Jen" <Jen@.discussions.microsoft.com> escreveu na mensagem
> news:8167FA52-468D-48BC-8D35-8F0E7BD69E46@.microsoft.com...
> this
need
> the
>|||Thanks, I do use min() to get the amount since some rows have null value, so
I need to use group, is there performance issue? Is it a good way or I need
to get all the rows back and let client to massage the data?
"Simon Worth" wrote:

> If you are aggrigating, yes, you would use group by instead of distinct.
> --
> Simon Worth
>
> "Bruno N" <nylren@.hotmail.com> wrote in message
> news:eB$VmrOJFHA.3596@.TK2MSFTNGP14.phx.gbl...
> need
>
>|||Group by limits the amount of records returned to your client, so it is a
good thing in that regard. Less traffic on the highway so to speak.
There's no need for the client application to loop through the records to
find the minimum amount for each group of records - the functionality is
built into SQL to accommodate aggregating data and should be utilized as
such.
Simon Worth
"Jen" <Jen@.discussions.microsoft.com> wrote in message
news:F65899CA-80FD-45F8-8401-92CAFECA272E@.microsoft.com...
> Thanks, I do use min() to get the amount since some rows have null value,
so
> I need to use group, is there performance issue? Is it a good way or I
need
> to get all the rows back and let client to massage the data?
> "Simon Worth" wrote:
>
the
of
query|||Jen,
From yr orig post
<<< I have a table with data that every 2 rows have same data for most of
cloumns (11), only 4 columns have different data. I would like to query this
table so that such rows appear as single row in the result ( I don't need th
e
4 cloumns),
Is the column you need the minimum from one of the 11, or one of the 4?
If it's one of the 11, then you can't group by the 11, you'll need t ogroup
by the remaining 10... The one you're aggregating on cannot be in the Group
By.
If it's one of the 4, then Iguess you DO need (at least one) of the 4, hmmm
?
"Jen" wrote:
> Thanks, I do use min() to get the amount since some rows have null value,
so
> I need to use group, is there performance issue? Is it a good way or I nee
d
> to get all the rows back and let client to massage the data?
> "Simon Worth" wrote:
>|||Yes, the minimum column if from one of 4 columns.
"CBretana" wrote:
> Jen,
> From yr orig post
> <<< I have a table with data that every 2 rows have same data for most of
> cloumns (11), only 4 columns have different data. I would like to query th
is
> table so that such rows appear as single row in the result ( I don't need
the
> 4 cloumns),
> Is the column you need the minimum from one of the 11, or one of the 4?
> If it's one of the 11, then you can't group by the 11, you'll need t ogrou
p
> by the remaining 10... The one you're aggregating on cannot be in the Grou
p
> By.
> If it's one of the 4, then Iguess you DO need (at least one) of the 4, hm
mm?
> "Jen" wrote:
>