Calculating difference based on prior entry in same table

  • Thread starter Thread starter Jessica
  • Start date Start date
J

Jessica

Greetings!

I have a database set up that has one table that has the
first time a fish was captured and tagged and then another
table that records the number of times the fish was
recaptured. Both these have a length and date field
within them and each fish has the tag number as the
primary key. I am able to calculate the days out and
difference in length from first capture, but also want to
do it from last capture. See below as an example.

Tagged Table
Tag ID Length Date
1 652 5/1/04
2 345 5/2/04

Recapture Table
Tag ID Length Date
1 658 6/1/04
1 701 7/2/04
1 659 8/15/04
2 350 6/2/04
2 600 10/10/04

How can I set up a query to calculate the date and length
differences BETWEEN recaptures (not from first capture)?
Do I need to do this in VB code instead and if so how?

Thanks!

Jessica
 
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