dbms_random gaussian

example.sql

SQL> select random_gauss(3,4,1,5) g from dual connect by level<=10;

         G
----------
4.86149705
3.62906844
2.55838621
1.38483471
2.02562505
2.70431185
1.56148613
1.46706992
3.69866968
1.30428931

10 rows selected.

random_gauss.sql

create or replace function random_gauss(p_mean number:=0, p_dev number:=1, p_min number:=null, p_max number:=null)
  return number
as
    res number;
    function gauss return number as
    begin
        return dbms_random.normal()*p_dev + p_mean;
    end;
begin
    res:=gauss();
    while not res between p_min and p_max loop
        res:=gauss();
    end loop;
    return res;
end;
/