Seems like an easy query, but isn't to me. Help?

[George Larson]

I hope I've come to right place, and I'm asking in the right way -- please
accept my apologies if not.

We have some dates missing and I need to populate those fields with dates
from the record just before them.  I've gotten this far:

SELECT UUid, MIN(DDenteredDate) minDate FROM UUtable JOIN DDdetail on DDid =
UUid
WHERE
UUdate IS NULL
GROUP BY UUid;

I can make this a sub-query and get the UUid of the record that I want to
copy UUdate from:

SELECT sub.UUid-1 as previous, sub.* FROM (
SELECT UUid, MIN(DDenteredDate) minDate FROM UUtable JOIN DDdetail on DDid =
UUid
WHERE
UUdate IS NULL
GROUP BY UUid;
)  as sub;

In this case, the field 'previous' is the UUid that I want to copy the
UUdate from and sub.UUid is where I want to copy to.

Does that even make sense?

Thanks,
George