Why does this query fail only SOMETIMES

[Database Administrator]

AC schreef:
> DELETE
> FROM PlayerRevisionScores
> WHERE RevisionID IN (SELECT RevisionID
> FROM Revision
> WHERE RevisionDate < (SELECT RevisionDate FROM Revision WHERE
> RevisionID = @nRev)
> AND ClubID = @nClubID)
>
> Revision Table - Primary Key is RevisionID, an Integer.
>
> Player Revision Scores, Primary Key is PlayerID and RevisionID.
>
> Subquery has no shot of returning more than 1 value, as RevisionID is the
> PK...
>
> PlayerRevisionScores has about 14000 rows in the 1 case where it fails, and
> while this query doesn't HAVE TO remove all rows, it is, int his
> installation, going to remove all 14000 rows most times... However, to
> handle all scenarios, the logic in place is accurate.
>
>

The instance where it fails, does the revisiondate in revision happen to
be NULL? I've had some weird stuff happening when comparing NULL values.


--
Rinze van Huizen
C-Services Holland b.v