SQL query

Hello everyone, I have a simple table containing just one column. Example test data unloaded to ascii file could be: 001,001,002,002,002,003,004,005,006,006,007,007,007 What I want to do is issue a select statement that groups together the 005, 006 and 007 as one such that I get the following output: 001,002, 003, 004, 999 where 999 represents the others. I don't fancy a bunch of selects UNIONed togther as the big scale version of this would mean having a whopping select statment. Any help given would be welcome. Thanks, Hamish.