translate returns char with all occurrences of each character in from_string replaced by its corresponding character in to_string. Characters in char that are not in from_string are not replaced. The argument from_string can contain more characters than to_string. In this case, the extra characters at the end of from_string have no corresponding characters in to_string. If these extra characters appear in char, then they are removed from the return value.

You cannot use an empty string for to_string to remove all characters in from_string from the return value. Oracle interprets the empty string as null, and if this function has a null argument, then it returns null.