best way to determine: string in numbers and > 0
What is the best way to determine, if input string (which is surely not null) is a positive whole number without comma, and bigger than zero.
The correct values are: 1,2,...,.
To determine if the string is a whole integer i can do this way:
select decode(REGEXP_INSTR ('1', '[^[:digit:]]'),0,'NUMBER','NOT_NUMBER') from dual;
But i don't know how to change the regular expression so that it would not allow zero to be first char.
Or is there any better way?