加快 Access 前端与 SQL Server 后端中整数日期的比较

Question

I'm using Microsoft Access as a front end to a SQL Server data warehouse. I need to speed up date comparisons in the front end. The dates are stored as integers in the back end (eg today is 20191123). In the Access front end I convert the integer dates to date data type:

CDate(Right([eventDate],2) & "-" & Mid([eventDate],5,2) & "-" & Left([eventDate],4))

That lets me do date comparisons. For example, to find occurrences of eventDate between today and 1 month from today I put this in the WHERE clause:

Between Date() And DateAdd("m",1,Date())

I need a faster way of doing this. My Access queries are reasonably fast without the date comparison in a WHERE clause, but as soon as I add the date comparison a query that previously ran in a fraction of a second takes 10-15 seconds.

Answer 1

您可以将您的访问日期转换为表字段的整数格式，然后使用：

Between Val(Format(Date(), "yyyymmdd")) And Val(Format(DateAdd("m",1,Date()), "yyyymmdd"))

Answer 2

Utilize SQL Server SQL engine which is waaay faster than Access!

Create pass-through query in Access, then pass the parameters in "ODBC Connect Str" and copy/paste your Access SQL to this query.

If the connection string is right and if the SQL syntax is correct, it will be executed on the SQL Server side and it should be a lot faster. I mean a LOT.

Your Connection string should look like this:

ODBC;DRIVER={SQL Server Native Client 11.0};SERVER=NameOfTheServer;DATABASE=NameOfTheDatabase;UID=Username;PWD=Password

Change the name of the driver if you are using a different one.

Note: you might want to change functions for date as those are not the same as in Access ie Date() in Access will be GETDATE() in SQL Server. CDate should be replaced with CAST or CONVERT, etc.