Question : Pulling Max Date But Keeping Null Value if a Record Has one

I have a table I am grouping by LEAD# and then pulling the max date from the CloseDT field for each group.  I am now having to deal with null fields in the CloseDT field.  What I need is if there is a null value in the CloseDT field for any of the records in the group then the MAX DT field needs to be null.  I am also pulling the minimum date for the OpenDT column, but there are no nulls there so you can ignore that part of the code below.

This is the code I've got so far -

SELECT tbl06SYSP.Lead, Min(tbl06SYSP.OPEN_DT) AS MinOfOPEN_DT, Max(tbl06SYSP.CLOSE_DT) AS MaxOfCLOSE_DT
FROM tbl06SYSP
GROUP BY tbl06SYSP.Lead;

Answer : Pulling Max Date But Keeping Null Value if a Record Has one

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