按时间而非日期查询parse.com

Question

Is there a way to query from parse.com CreatedAt column by the time only? My goal is to query all the records that were CreatedAt between say 6 and 12 o'clock regardless of the date (though I will need to attach some date range also). I am using parse's .NET API. In my mind I thought something like this might work, but sadly all I got was InvalidOperationException :

pQuery = from hit in pQuery 
    where ((DateTime)hit.CreatedAt).Hour >= 6 
       && ((DateTime)hit.CreatedAt).Hour <= 12
    select hit;

Of course I always could filter results after the query using business logic, but that would hinder the performance. Would love a query solution.

Answer 1

I don't think you can do it the way you're thinking - the createdAt field is just a UNIX timestamp. Instead, you could try adding a new field (or fields) to track the time. Create a beforeSave method for that class that populates those fields anytime a new object gets created. Then you can query against those new fields.

The tricky part here will be dealing with timezones, so take that into consideration.