I'm using a formula, learned on this forum, to count only unique records within a sumproduct formula.
=SUMPRODUCT(($B$18:$B$741>=C4)*($B$18:$B$741<=C5)*(1/COUNTIF($D$18:$D$741,$D$18:$D$741)))
C4 and C5 are dates - I wish to include records within two date ranges. The data in column D are...