I'm not exactly sure if you are asking us how to find the last set of digits following the last dash .. or if you are asking for us to help you witht he SQL statement to combine the like numbers and find the highest dash number.

But .. if you are just asking how to find the last set of numbers when there could be unknown numbers of dashes and unknown length of digits, this would work:

? SUBSTR(Somefield,RAT('-', Somefield)+1)

>I need a Select statement to find the last dash number in a series of partnumbers. Each record in my table has a unique sequence number. The table contains all partnumbers. The greatest sequence number represents the last partnumber that was entered and thus will be the last or greatest dash number for that series. So I need to isolate a series of partnumbers, records where the first six numbers are the same, then figure out from the dash suffixs(-401, -403, -405) which is the greatest.
>
>The table is accessed remotely by SPT.
>
>This is needed to control what the next dash number the user can create is.