Hi ,
The helper columns have been added only to make it easier to verify whether entries fulfill all the requirements.
The formula in column Q is :
=IF(COUNTIFS($C$6:$C$1050, C6, $D$6:$D$1050, D6) > COUNTIFS($C$6:$C6, C6, $D$6:$D6, D6), "", 1)
What this is checking for is whether the combination of serial number and date code in columns C and D is unique or whether there are multiple such entries ; if there are multiple entries only the last entry will be flagged with 1 , and earlier entries will have blanks.
The formula in column R is :
=IF(Q6 = 1, IF(SUMPRODUCT((RawData!$G$6:$G$298 ="Closed") * (RawData!$E$6:$E$298 = C6) * (RawData!$F$6:$F$298 = D6)) > 0, 1, ""),"")
which checks for whether there is a corresponding entry in the RawData tab , which has the same serial code and date code and a status of Closed.
These two helper column formulae can be incorporated in the main formula in column M , but then this formula will become a lengthy one , and will not be readable. Splitting the formula using helper columns makes it easy to read and visualize where things have gone wrong if the output in column M is not what it should be.
Narayan