Hi all, thanks for the suggestions so far. However, this definitely seems
to be down to the size of the table more than anything else.
Beyond a certain size MIN(), MAX() and TOP 1 all stop working even though
SYS(3054) still reports full optimization! Any ideas if this max working
table size can be changed by some memory setting or other?
Example:
SELECT TOP 1 OrdNo FROM OrdersNoOnly WHERE OrdNo > cLastOrdNo ;
AND Left(OrdNo,1) = cDept ORDER BY OrdNo
* takes 50 seconds
SELECT OrdNo FROM Orders INTO TABLE OrdersNoOnly
INDEX ON OrdNo TAG OrdNo
INDEX ON LEFT(OrdNo,1) TAG Dept
SELECT TOP 1 OrdNo FROM OrdersNoOnly WHERE OrdNo > cLastOrdNo ;
AND Left(OrdNo,1) = cDept ORDER BY OrdNo
* takes 0.7 seconds
Nick
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf
> Of NickC
> Sent: 07 September 2008 18:18
> To: 'ProFox Email List'
> Subject: RE: SQL > not optimised
>
> Slight progress but no idea why!
>
>
> Three ways that don't work (too slow):
>
> SELECT MIN(OrdNo) FROM Orders WHERE OrdNo > cLastPONum
>
> SELECT TOP 1 OrdNo FROM Orders WHERE OrdNo > cLastPONum ORDER BY OrdNo ASC
>
> SELECT * FROM Orders WHERE OrdNo IN ;
> (SELECT TOP 1 OrdNo FROM Orders WHERE OrdNo > cLastPONum ;
> ORDER BY OrdNo ASC)
>
>
> And one way that does work:
> SELECT OrdNo FROM Orders WHERE OrdNo > cLastPONum ORDER BY OrdNo INTO
> CURSOR
> Temp1
> cOrdNo = Temp1.OrdNo
>
> However put a MIN, MAX or TOP 1 on and it goes excruciatingly slow again.
>
> Nick
>
>
>
>
[excessive quoting removed by server]
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