Rik Wasmus wrote:
> On Wed, 02 Jan 2008 17:21:26 +0100, Norman Peelman <npeelman@cfl.rr.com>
> wrote:
>
>> Rik Wasmus wrote:
>>> On Tue, 01 Jan 2008 14:07:54 +0100, php_mysql_beginer911
>>> <deepakgc@gmail.com> wrote:
>>>
>>>> Hi everyone ..
>>>>
>>>> i am wondering if it is possible to update a field where filed values
>>>> are null
>>>>
>>>> with increment values
>>>>
>>>> i can do same in php by using a loop and updating a field
>>>>
>>>> for($i=1;$i<=mysql_num_rows($result);$i++ )
>>>> {
>>>> $sql="UPDATE table SET col=$i ORDER BY col_date DESC";
>>> I don't think that's what you want...
>>>
>>>> }
>>>>
>>>> is it possible wihout using any php loop
>>>>
>>>> i use when fields have values
>>>>
>>>> update table set col=col+1 where .....
>>>>
>>>> but couldn't find anywhere how to do when values are 0 or null with
>>>> only mysql query
>>> I'm going to guess this is what you want:
>>> SET @myVar := 0;
>>> UPDATE table SET col = @myVar := @myVar + 1 ORDER BY col_date DESC;
>>> So, just 2 'queries' to call in MySQL.
>>
>> It should work just fine if the column value is 0, NULL is the
>> issue. Since NULL is not a value there is nothing to add 1 to. I would
>> have to say this is the expected behavior. But, I suppose it would be
>> ok if it worked that way too.
>
> You're not working with the previous column value, so wether 'col' holds
> NULL,0, or 'thisisjustastring', it will just be overwritten with the
> integer from @myVar. You're effectively making an entire new 'order'
> with this. If previous values have to be taken into account I have
> misunderstood the question.
> --Rik Wasmus

I'm sorry, I meant that as a response to the OP...

--
Norman
Registered Linux user #461062