The Field value (middle condition) should be the single cell January!E4.. which tells Excel with Field (column) to add...
e.g
=DSUM('January Sales'!$A$4:$K$50,'January Sales'!E4,G16:H17)
Note: G21 in the Summary table has an extra space after the "S".. please remove or you will get 0 result.
Check all others for this inconsistency too.
Bookmarks