Class or filter expression on date field in shapefile

[Ei Fujioka]

Thanks, Andreas, for your quick response.

This is exactly what I wanted to know.
It seems Mapserver 4.2 doesn't treat backticks as a date type value, 
though. So definitely need to upgrade.
Meanwhile I think I should stick to numeric values.

Ei

Andreas Albarello wrote:
> Ei Fujioka wrote:
>> I'm having difficulty in trying to filter features in a shapefile by 
>> dates.
>>
>> I looked into this mailing list and have found a post saying 
>> "MapServer doesn't support date types in shapefiles."
>> This post is a very old one, dated in July 2000.
>>
>> So I'm wondering if the latest Mapserver supports this. And if so, 
>> what is the date format for class/filter expression?
>> I use Mapserver 4.2.
> 
> Ei,
> 
> yes, this should be possible with more recent MapServer releases. I 
> don't know whether it used to work back in the day of MapServer 4.2. You 
> should really upgrade to 4.6 at least.
> 
>> Can't I use a string value like '2003-03-01' for date comparison?
>> I tried the following expression but failed.
>> EXPRESSION ([DATE_S] > '2003-01-01')
>>
>> Is there any smarter way to filter on dates?
> 
> Yes, you need to explicitly tell MapServer that you want the field and 
> your value to be treated as dates rather than strings. You do this by 
> surrounding them with backticks (ASCII #96), for instance:
> 
> EXPRESSION (`[DATE_S]` > `2003-01-01`)
> 
> Best regards,

-- 
======================
   Ei Fujioka
   Research Associate
   Duke University

   (919) 613-8021
   efujioka at duke.edu
======================