Hi, I've seen various Postgres examples here and elsewhere that deal with the old common-prefix problem (i.e. "given 1234 show me the longest match").
I'm in need of a bit of guidance on how best to implement an alternative take. Frankly I don't quite know where to start but I'm guessing it will probably involve CTEs, which is an area I'm very weak on. So, without further ado, here's the scenario: Given an SQL filtering query output that includes the following column: 87973891 87973970 87973971 87973972 87973973 87973975 87973976 87973977 87973978 87973979 8797400 The final output should be further filtered down to: 87973891 8797397 8797400 i.e. if $last_digit is present 0–9 inclusive, recursively filter until the remaining string is all the same (i.e. in this case, when $last_digit[0-9] is removed, 8797397 is the same). So, coming back to the example above: 8797397[0-9] is present so the "nearest common" I would be looking for is 8797397 because once [0-9] is removed, the 7 is the same on the preceeding digit. The other two rows ( 87973891 and 8797400) are left untouched because $last_digit is not present in [0-9]. Hope this question makes sense ! Laura
