Having trouble getting the DSum function to generate a running total by groups.  My query has a field that is coded as:  RT: DSum("[Sum of Totbush]","[TransmasTotalsCornQ1]","CropYr=" & [CropYr] And "No<=" & [No]).  The CropYr and No fields are number fields that are sorted in ascending format.  When the query is run, I get a sum total for all the groups for each record.  If I remove the second part of the criteria that evaluates the No field, the query will produce a running total for each crop year for each record.  I need for the query to produce a running total of the "Sum of Totbush" field that is reset for each change in crop year, but is sum totaled by each month (ie No) in the year.  

Thanks in advance for your assistance.

Screen shot follows:
CropYr Sum Of Totbush Month No RT FiscalMonth MName CompNo
2017 12382.8628 6 24209 1718818.2299 1 Jun 24209
2017 9579.6429 8 24211 1718818.2299 3 Aug 24211
2017 34537.7964 9 24212 1718818.2299 4 Sep 24212
2017 38238.92 10 24213 1718818.2299 5 Oct 24213
2017 55374.2785 11 24214 1718818.2299 6 Nov 24214
2017 62170.0169 12 24215 1718818.2299 7 Dec 24215
2017 13425.3557 1 24216 1718818.2299 8 Jan 24216
2017 29144.9914 2 24217 1718818.2299 9 Feb 24217
2017 786.0714 3 24218 1718818.2299 10 Mar 24218
2017 9821.4256 4 24219 1718818.2299 11 Apr 24219

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Reply from Alex Hedley:

This blog post may help.