Comparing number with varchar2 - oracle

Question

I have this function and I need to compare number with varchar.
CREATE OR REPLACE FUNCTION getOdds(i_odd in varchar2, i_id in number) return number as
begin
declare odd integer;
declare i_perecentage=0;
begin
if i_odd ='SP'
then
return (0);
end if;
odd:=round(to_number((1-i_perecentage/100)*i_odd),2);
if odd<1
then
return(i_odd);
else
return(round(odd,2));
end if;
end;
end;
/
PS: I edited function and i resolve problem with comparing , now i have another situation that i dont like..
This function returns calculated percentage of i_odd. The problem is that if i pass 0 in i_percentage in results i get result with no decimal places(for example: i_odd = 3.10 and i_percentage = 0 i get odd = 3 but if I pass i_odd = 3.10 and i_percentage = 1 i get odd = 3.10 ).
Why is on i_percentage = 0 i dont get decimal places ??

Answer 1

If you want to validate a varchar2 field as a number in PL/SQL, typically you'd just try converting it to a number and catch the exception.
CREATE OR REPLACE FUNCTION getOdds(i_odd in varchar2, i_id in number) return number as
odd number;
BEGIN
-- if i_odd = 'SP' (or another non-number), this will throw an ORA-01722
-- exception which will be caught in the exception block, below
odd := to_number(i_odd); -- you might want a format mask here
--... now you can use "odd" as a number
EXCEPTION WHEN INVALID_NUMBER THEN
return 0;
END;
/
You can also nest a begin..end block in the middle of your code just to catch exceptions, if that works better for you:
CREATE OR REPLACE FUNCTION getOdds(i_odd in varchar2, i_id in number) return number as
odd number;
begin
begin
odd := to_number(i_odd); -- you might want a format mask here
exception when INVALID_NUMBER then
odd := 0;
end;
--... now you can use "odd" as a number
end;
/

Answer 2

The reason why you can't catch the invalid_number exception is because you are declaring the input parameter as a number. When you call your function, Oracle tries to convert the string to a number first (and it fails of course, before entering your code at all).
If you change the input parameter to varchar2, then the conversions to number (implicit in this case) is done inside the function, and invalid numbers can be caught and handled as you want (here I'm just returning a different string to denote the issue):
create or replace function is_odd_even(i_num in varchar2)
return varchar2
is
begin
-- conversion to number is done here
if (mod(i_num, 2) = 0) then
return 'EVEN';
else
return 'ODD';
end if;
exception
when INVALID_NUMBER or VALUE_ERROR then
-- do something meaningful
return 'INV';
end;
Usage example:
with x as (
select '1' as val from dual
union all
select 'SP' as val from dual
union all
select '2' as val from dual
)
select x.val, is_odd_even(x.val)
from x;
Output:
1 ODD
SP INV
2 EVEN

Answer 3

SOLUTION:
CREATE OR REPLACE FUNCTION getOdds(i_odd in varchar2, i_id in number) return varchar2 as
odd varchar2(10);
ret_value number(4);
begin
if (i_odd ='SP') or i_odd is null then
return 'SP';
else
odd :=ROUND( TO_NUMBER( ( 1 - (play_beting.get_odds_percentage(i_id) / 100 ) ) * TO_NUMBER(i_odd) ), 2);
IF(odd < 1) THEN
ret_value := TO_NUMBER(i_odd);
ELSE
ret_value := to_char(odd,'9999.00');
END IF;
END IF;
RETURN to_char(ret_value,'9999.00');
END getOdds;