FUNCTION `sp_dec2hex`( IN xvalue BIGINT ) RETURNS CHAR(16);

/*
    Funkce pro převod desítkové na šestnáctkovou, přidán xtemp 
    protože jinak SUBSTRING nejde s bigintem dohromady
    maximum dec: 9223372036854775807 hex: 7FFFFFFFFFFFFFFF 
*/

BEGIN
  DECLARE xseq CHAR(16);
  DECLARE xresult CHAR(16);
  DECLARE xdigit CHAR(1);
  DECLARE xtemp smallint;

  SET xseq = "0123456789ABCDEF";
  SET xtemp = (xvalue mod 16)+1;
  SET xresult = SUBSTRING(xseq FROM xtemp FOR 1);
  
  WHILE xvalue > 0  DO
    SET xtemp = (((xvalue DIV 16) MOD 16)+1);
    SET xdigit = SUBSTRING(xseq from xtemp FOR 1);
    SET xvalue = xvalue DIV 16;
    IF xvalue <> 0 THEN 
      SET xresult = xdigit + xresult; 
    END IF;
  END WHILE;
    
    RETURN xresult;
END