Calculating a Sum Value on a report in Access

问题

I have a report that is supposed to show the Stock Value of products before and after conversion.

I have the source products product code and stock value displayed on the form, now I need to get the value of the items converted from that one piece of stock.

I assumed this would be possible to achieve using some simple SQL to calculate the sum of all resulting products with the same SCID (Stock Conversion ID). My SCID is used to link a source product to a number of resulting products in a different table.

In this image I have named the SCID boc in the detail section sSCID to try and differentiate it from any fields in tables that it may try to pick up. But basically I need to get the code to look for result products that match the SCID displayed in that box and add them all together to get the sum total of converted stock.

If context helps I am trying to create a form that shows the value of stock before and after a conversion process in order to try and calculate the wastage.

Thanks, Bob P

回答1:

You can either use DSum or build your report query to include the calculation. I would prefer the second option. This assumes that SCID is numeric, you would need quotes for a text SCID.

=DSum("sValue","[Stock Conversion Items]","SCID=" & sSCID)

Or

 SELECT r.This,r.That,s.ConvValue 
 FROM ReportTable r
 INNER JOIN (
      SELECT SCID, Sum(sValue) As ConvValue 
      FROM [Stock Conversion Items]
      GROUP BY SCID) s
 ON r.sSCID = s.SCID

The above query uses aliases r and s for the tables : ReportTable r or ReportTables As r

来源：https://stackoverflow.com/questions/13120982/calculating-a-sum-value-on-a-report-in-access