Question

I have come across an SQL statement where one of the conditions is comp_cd > to_char('0000000000','9999999999').

Running select to_char('0000000000','9999999999') from dual i am getting the result “0”.

Does anyone has come across this?

Answer 1

The function TO_CHAR expects a NUMBER or DATE as its first parameter, but you’re providing a string ('0000000000') instead.

Therefore, Oracle uses an implicit conversion to convert it to a NUMBER first; '0000000000' is converted to the number 0.

Then, TO_CHAR converts 0 back to a string using the '9999999999' format model. This should result in the string:

'          0'

Finally:

comp_cd > '          0'

would do a lexical (alphabetical) comparison between two strings.