Denisa: On Mon, Feb 5, 2018 at 2:34 PM, Denisa Cirstescu <Denisa.Cirstescu@xxxxxxxxxx> wrote: > I need an SQL function that eliminates all ASCII characters from 1-255 that > are not A-Z, a-z, 0-9, and special characters % and _ so something like: Are you aware ASCII is a SEVEN bit code ? And now, why don't you just write the negated condition, maybe throwing in a null to avoid it? Do you have codes above 255 which you do not need replacing? I.e., something like SELECT regexp_replace(p_string, E'[^A-Za-z0-9%_]', '', 'g')); This will also zap \0 and all chars >255 if you are using unicode, if this is not a problem that's all there is to it. If you are using it you could throw a null plus a character range from 256 to the largest one, but I doubt this is useful. Which is the character set of your source data? ( It can NOT be ascii if you are worried about 128-255, but is it a single byte one or is it unicode or something wide ? ) Also, it may perform a bit faster if you throw a + after the character class ( for >1 char runs ). Francisco Olarte.