Sorry I don't understand your question. I thought you were referring to the 
lack of DATE type in Hive. HiveQL has the similar syntax with SQL like 
count(distinct col). Your regular SQL query should work together with the help 
of UDFs I mentioned.

On Oct 15, 2010, at 9:43 AM, Vijay wrote:

Thanks, Ning! Finding the date which is 30 days before/later was easy enough 
but my problem is beyond that. I need to find unique users based on these last 
30 days for a range of days. Does that make sense?

On Fri, Oct 15, 2010 at 12:10 AM, Ning Zhang 
<nzh...@facebook.com<mailto:nzh...@facebook.com>> wrote:
There are some UDFs that convert a string to epoch time and back to a string.  
e.g.,

select from_unixtime(unix_timestamp('2010-10-10', 'yyyy-MM-dd') + 60*60*24*30, 
'yyyy-MM-dd') from src limit 1;

 will given you the date which is 30 days later than 2010-10-10.

On Oct 14, 2010, at 11:36 PM, Vijay wrote:

> Hi, I need help with this scenario. We have a table of events which has 
> columns date, event (not important for this discussion), and user_id. It is 
> obviously easy to find number of unique users for each day. I also need to 
> find number of unique users in the last 30 days for each day. This is also 
> quite simple to do for one day. However, I cannot figure out how to do this 
> for a range of days. Something like this is pretty straightforward in most 
> RDBMS but with HiveQL has I'm finding this hard. I might be missing something 
> simple though. Any help is appreciated. Ideally the query should also be as 
> optimized as possible as this table could be huge.
>
> Thanks,
> Vijay
>



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