"Radoulov, Dimitre" wrote...
>
> "Jeff Gardner" wrote...
>> Jeff Gardner wrote:
>>> Radoulov, Dimitre wrote:
>>>> "Jeff Gardner" wrote...
>>>>> Greetings:
>>>>>
>>>>> I am trying to locate incorrect data in a column using REGEXP. Only
>>>>> numeric data is allowed but I am importing data, some of which is not
>>>>> properly formatted. I am using:
>>>>>
>>>>> SELECT *
>>>>> FROM `table`
>>>>> WHERE `column` REGEXP "[^[:digit:]]";
>>>>>
>>>>> to locate any value that is not a number. I've tried several
>>>>> variations and I get an empty set back. I know that there are illegal
>>>>> characters in some of the data but I can't seem to locate it using
>>>>> this query. The field can contain anywhere from 1 to 6 digits, if
>>>>> that is relevant. Advice is much appreciated.
> [...]
>> It turns out that there were 13 rows with a NULL value in the field in
>> question. NULL is not whitespace, nor is it digits. Any explanation as
>> to why the above query returned no rows?
>
> Because of its special meaning, I suppose.
>
> "Conceptually, NULL means "a missing unknown value" and it is treated
> somewhat differently from other values. "



> Unknown means that you cannot _know_ whether it's a digit or something
> else (btw, whitespaces are handled correctly with your example query).


I ment "as you very likely expect", not "correctly"


Regards
Dimitre