LARRY: The assumptions are correct. Your example below to also correct.
Assuming that each measurement (10, 20, etc) is in a separate row in a table, and assuming that each drill hole has an ID value that is consistent across all depth measurements for that hole then yes, this is a classic instance in which you'd use a cursor. EG: HoldID Depth Measurement FilterValue 101 10 154 101 20 96 101 30 100 There are two different ways you could write the cursor -- either storing three consecutive measurements as you traverse the table in code and then UPDATEing the record one place "behind" the last measurement you're looking at, or else using a SELECT INTO on each record to get the measurements before and after the current record and UPDATEing the current record in the cursor. The number of measurements is variable. That is the hole depth varies. If the number of measurements and the depth at which they were taken is consistent for all holes, you could also create a denormalized view of the data which would allow you to do the filtering with a series of update commands: HoldID Depth10Measure Depth20Measure Depth30Measure 101 154 96 100 This is done by creating a view with a lot of IFEQ() functions and a GROUP BY clause. It can be very advantageous for reporting purposes, but reliese on the regularity of the data. See my second post on this subject. But it seems that you understand my problem. I would appreciate any hints of how to get started. Eventually there would be some look up values for other corrections but these would onlywork on a row by row basis. Finally, it's possible in standard SQL to write a SELECT statement that can get the values before and after the row you're operating on, but it's a bit tricky and I'm not sure that R:Base supports the full syntax. If you post the actual structure of your table I'll see if I can come up with something. That would let you update your filter values with one and only one SQL statement. -- Larry Thanks Joe DB Drake-Brockman Geoinfo Pty Ltd 25 Deague Court North Perth 6006 Tel / Fax 08 9328 4891 Mob 0427 525952 Email <mailto:[EMAIL PROTECTED]> [EMAIL PROTECTED]
