multiple tables w/ dates; need concurrent data only in each

[Guest]

Hello,

I have eight tables in an Access personal database in Office 2K3. Each
table has ~150,000 records that cover a similar time period; the data are
records of environmental variables taken every fifteen minutes.

There is one field for date (Date/Time) and one field for time
(Date/Time). Due to error in the recording devices and device maintenance,
there are times when each device was off (one table for each device) and thus
the temporal ranges of the data are different for the different tables.

I need somehow to perform a function that returns only the records that
are concurrent in all eight tables, a sort of intersection of the data, so
that the tables are exactly concurrent with one another temporally.

Any idea how I could go about this?

Thanks,

S Taylor
NCSU

 

[Joseph Meehan]

Hello,

I have eight tables in an Access personal database in Office 2K3. Each
table has ~150,000 records that cover a similar time period; the data are
records of environmental variables taken every fifteen minutes.

There is one field for date (Date/Time) and one field for time
(Date/Time). Due to error in the recording devices and device
maintenance,
there are times when each device was off (one table for each device) and
thus the temporal ranges of the data are different for the different
tables.

I need somehow to perform a function that returns only the records that
are concurrent in all eight tables, a sort of intersection of the data, so
that the tables are exactly concurrent with one another temporally.

Any idea how I could go about this?

Thanks,

S Taylor
NCSU

If I understand all this, I suggest a query joined on the date time.
Then filter out all the nulls.

If you like you should be able to set up a relationship in a query that
will show only those records that are in both sources. I have not played
with this one that often so you may need to cascade a couple of queries to
get to what you want.