Depends. If this is a correlation table and the combined columns are a
primary key,
SELECT ObjId,
COUNT(ElemId)
FROM Elems
GROUP BY ElemId;
if the combination is not unique, then:
SELECT ObjId,
COUNT(DISTINCT ElemId)
FROM Elems
GROUP BY ElemId;
----- Original Message -----
From: "Csaba Gabor" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Friday, June 07, 2002 10:20 AM
Subject: Counting distinct elements
> Seems like this should be an easy question, but I just don't get it:
>
> If I have CREATE TABLE Elems (ObjId INT, ElemId INT);
> Is there a nice query to find the Number of Distinct ElemId's for each
ObjId?
>
> Motivation: Later I will want to add a WHERE ObjId IN (...) and join the
Obj describing table to
> the results of this query.
>
> Thanks,
> Csaba Gabor from New York
>
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