RavenDB Map/Reduce with grouping by date - mapreduce

Question

I have to create a query to get a statistic by post per year/month, e.g. group by date. I created an index:
public class Posts_Count : AbstractIndexCreationTask<Post, ArchiveItem>
{
public Posts_Count()
{
Map = posts => from post in posts
select new
{
Year = post.PublishedOn.Year,
Month = post.PublishedOn.Month,
Count = 1
};
Reduce = results => from result in results
group result by new {
result.Year,
result.Month
}
into agg
select new
{
Year = agg.Key.Year,
Month = agg.Key.Month,
Count = agg.Sum(x => x.Count)
};
}
}
In studio I have next map and reduce functions:
Map:
docs.Posts.Select(post => new {Year = post.PublishedOn.Year, Month = post.PublishedOn.Month, Count = 1})
Reduce:
results
.GroupBy(result => new {Year = result.Year, Month = result.Month})
.Select(agg => new {Year = agg.Key.Year, Month = agg.Key.Month, Count = agg.Sum(x => ((System.Int32)(x.Count)))})
But the problem is I alway get a null values of Year and Month properties:
{
"Year": null,
"Month": null,
"Count": "1"
}
Can anybody help me to resolve the issue with my code? Thank You!

Answer 1

Your code looks fine. I tested it and it works in the current unstable build 1.2.2096. There have been some discussion around this lately on the RavenDB google group, so perhaps it was broken previously. Try again with the current build and see if it works for you now.