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Posted by Ed Murphy on 09/21/06 13:17
yicong wrote:
> could you tell me which case is more efficiency?(my tables have no index)
Add some indexes!
> And does it has any else case more efficiency?
I would write it as follows, for clarity:
select sum(Invoice_Production.Quantity)
from [Invoice_Production]
join [Invoice] on [Invoice].InvoiceNo = [Invoice_Production].InvoiceNo
join [users] on [users].user_id = [invoice].DealerNo
join [dat_Item] on [dat_Item].ItemCode = [Invoice_Production].ItemCode
join [dat_MachineType] on [dat_MachineType].MachineTypeID =
[dat_Item].MachineTypeID
where [Users].User_ID = '"& rs2(0) &"'
and Invoice.Cyear between "&startYear&" and "&endYear&"
and Invoice.Cmonth between "&startMonth&" and "&endMonth&"
Also, you can remove dat_Item and dat_MachineType entirely (unless you
might have null values with non-zero quantities, and want to exclude
those from the total).
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