create or replace function getmidtime(
A1 date,
B1 date,
A2 date,
B2 date,
A3 date,
B3 date
) return number
as
v_h number;
v_a date;
v_b date;
begin
if A1>A2 then v_a:=A1; else v_a:=A2; end if;
if A3>v_a then v_a:=A3;end if;
if B1<B2 then v_b:=B1;else v_b:=B2;end if;
if B3<v_b then v_b:=B3;end if;
if v_a<v_b then return (v_b-v_a)*24;esle return null;end if;
end;
/
Date Values
A later date is considered greater than an earlier one. For example, the date equivalent of '29-MAR-1997' is less than that of '05-JAN-1998' and '05-JAN-1998 1:35pm' is greater than '05-JAN-1998 10:09am'.