Create a function with optional arguments in MySQL

Question

I want to create a function with optional arguments in MySQL. For instance, I want to create function that calculates the average of its arguments. I create a function of fi

Answer 1

While far from an ideal solution, here's how I solved optional parameters for a concat function I needed:

delimiter ||
create function safeConcat2(arg1 longtext, arg2 varchar(1023))
 returns longtext
 return safeConcat3(arg1, arg2, '');
||

create function safeConcat3(arg1 longtext, arg2 varchar(1023), arg3 varchar(1023))
 returns longtext
 return safeConcat4(arg1, arg2, arg3, '');
||

create function safeConcat4(arg1 longtext, arg2 varchar(1023), arg3 varchar(1023), arg4 varchar(1023))
returns longtext
  begin
      declare result longText;
      set result = concat(arg1, arg2, arg3, arg4);
      if( result is null) then
          set result=arg1;
      end if;
      return result;
  end
||

Note: This means you have to call the method that corresponds to the number of args.