Please help with this formula.
=ARRAYFORMULA(if(A3:A$900="";"";IF(DATEVALUE(History!C$3:C$900)<D3:D900;SUMIF(History!A$3:A$900;A3:A900;C$3:C$900)*SUMIF(History!A$3:A$900;A3:A900;History!B$3:$B900);"")))I want to SUM C3:C900 if the dates in History!C3:C900 are less than the dates in Data!D3:D900