I have to perform the following SQL query:
select answer_nbr, count(distinct user_nbr)
from tpoll_answer
where poll_nbr = 16
group by answer_nbr
The LINQ to SQL query
from a in tpoll_answer
where a.poll_nbr = 16 select a.answer_nbr, a.user_nbr distinct
maps to the following SQL query:
select distinct answer_nbr, distinct user_nbr
from tpoll_answer
where poll_nbr = 16
So far, so good. However the problem raises when trying to GROUP the results, as I'm not being able to find a LINQ to SQL query that maps to the first query I wrote here (thank you LINQPad for making this process a lot easier). The following is the only one that I've found that gives me the desired result:
from answer in tpoll_answer where answer.poll_nbr = 16 _
group by a_id = answer.answer_nbr into votes = count(answer.user_nbr)
Which in turns produces the follwing ugly and non-optimized at all SQL query:
SELECT [t1].[answer_nbr] AS [a_id], (
SELECT COUNT(*)
FROM (
SELECT CONVERT(Bit,[t2].[user_nbr]) AS [value], [t2].[answer_nbr], [t2].[poll_nbr]
FROM [TPOLL_ANSWER] AS [t2]
) AS [t3]
WHERE ([t3].[value] = 1) AND ([t1].[answer_nbr] = [t3].[answer_nbr]) AND ([t3].[poll_nbr] = @p0)
) AS [votes]
FROM (
SELECT [t0].[answer_nbr]
FROM [TPOLL_ANSWER] AS [t0]
WHERE [t0].[poll_nbr] = @p0
GROUP BY [t0].[answer_nbr]
) AS [t1]
-- @p0: Input Int (Size = 0; Prec = 0; Scale = 0) [16]
-- Context: SqlProvider(Sql2008) Model: AttributedMetaModel Build: 3.5.30729.1
Any help will be more than appreciated.