How to convert any datatype to a number

Question

Hi --
I have a query I'm writing, and for error-trapping purposes I want to convert whatever information I received in a bind variable into a number.
For instance, in my query:
SELECT TO_NUMBER('c') FROM dual
I get an error because 'c' is not a number. I'm usually expecting a number, but if for some reason I receive a character, I want to convert that character to a zero, and if I do receive a number I want it to retain its value. I hope this is clear!!!
Any suggestions are greatly appreciated.
Thanks,
Christine

Answer 1

Unfortunately, I need to do this directly in the SQL statement if at all possible.If you don't want to use a function, try :
  1  select case when ascii('&1') between 48 and 57 then to_number('&1')
  2              else 0 end
  3* from dual
SQL> /
Enter value for 1: a
Enter value for 1: a
old   1: select case when ascii('&1') between 48 and 57 then to_number('&1')
new   1: select case when ascii('a') between 48 and 57 then to_number('a')
CASEWHENASCII('A')BETWEEN48AND57THENTO_NUMBER('A')ELSE0END
                                                         0
SQL> /
Enter value for 1: 5
Enter value for 1: 5
old   1: select case when ascii('&1') between 48 and 57 then to_number('&1')
new   1: select case when ascii('5') between 48 and 57 then to_number('5')
CASEWHENASCII('5')BETWEEN48AND57THENTO_NUMBER('5')ELSE0END
                                                         5
SQL> Nicolas.
ascii(9) => 57
Correction for ascii(0) => 48 and not 49...
Message was edited by:
N. Gasparotto