StackOverflow response times by language, grouped by hour

response time by hour.sql

DECLARE @tagname varchar(20) = ##language:string##

select ResponseHour, 
       avg(cast(ResponseTime as bigint)) as Average,
       stdev(cast(ResponseTime as bigint)) as StandardDev
from 
  (SELECT
         Questions.CreationDate, 
         Questions.Title, 
         Tags.TagName,
         Answers.CreationDate as ResponseDate,
         datediff(minute, Questions.CreationDate, 
                          Answers.CreationDate) as ResponseTime,
         cast(DATEPART(hour, Questions.CreationDate) as int) as ResponseHour
    FROM Posts Questions
    join Posts Answers on Answers.id = Questions.AcceptedAnswerId
                         and datediff(hour, Questions.CreationDate, Answers.CreationDate) < 5
    join PostTags ON PostTags.PostId = Questions.Id
    join Tags on Tags.Id = PostTags.TagId
    WHERE Questions.CreationDate > convert(datetime, '01/01/2012', 101)  
    and TagName = @tagname
) as Responses
group by ResponseHour
order by ResponseHour