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From:PJ Date:February 17 2009 7:17pm
Subject:Re: how to check for null in string
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Johan De Meersman wrote:
> In SQL, the correct syntax is "IS NULL" or "IS NOT NULL".
>
> Random programming languages more often than not have no decent
> support for
> NULL content, although your DB library might have an isnull() function or
> something similar. Once you've exported a field into a regular variable,
> however, most often NULL becomes indistinguishable from an emtpy string.
>
>
> On Tue, Feb 17, 2009 at 2:47 AM, PJ <af.gourmet@stripped> wrote:
>
>> I know this is not working, but how can I check for NULL; or how can I
>> configure my field "sub_title" so I can check if $booksub_title contains
>> anything or is empty.
>> This problem as been breaking my back...don't know what to put in as a
>> default to be able to check against string input (VARCHAR) or should I
>> use another type?
>>
>> if ($booksub_title != NULL) {
>> echo "<td width='400'><b>$booktitle[$i]</b><br>
>> $booksub_title[$i]</b>";
>> }
>> else {echo "<td width='400'><b>$booktitle[$i]</b>";
>> }
>>
>> --
>>
>> Phil Jourdan --- pj@stripped
>> http://www.ptahhotep.com
>> http://www.chiccantine.com
>>
>>
>> --
>> MySQL General Mailing List
>> For list archives: http://lists.mysql.com/mysql
>> To unsubscribe: http://lists.mysql.com/mysql?unsub=1
>>
>>
>
>
Problem resolved.
The hic in this was not the null but rather the variable. I finally
understood that the problem in the code was the variable $booksub_title
- since it comes up in a loop it is changed on every pass, therefore the
string should be $booksub_title[$i] to correspond to the same string in
the else statement... this is what works, now:

if (empty ($booksub_title[$i])) {
   echo "<td width='400'><b>$booktitle[$i]</b><br>";
        }
   else {echo "<td
width='400'><b>$booktitle[$i]</b><br>$booksub_title[$i]<br>";
        }

so there! Thanks all for your input which did help me to see the light,

-- 

Phil Jourdan --- pj@stripped
http://www.ptahhotep.com
http://www.chiccantine.com
Thread
how to check for null in stringPJ17 Feb
  • Re: how to check for null in stringJohan De Meersman17 Feb
    • Re: how to check for null in stringJoerg Bruehe17 Feb
    • Re: how to check for null in stringPJ17 Feb