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Just trying out F# 3.0 and hit a bit of a wall when it comes to grouping by multiple columns. The obvious thing to try was query { for d in context.table do groupBy (d.col1,d.col2) into g select (g.Key) } But I get a "Only parameterless constructors and initializers are supported in LINQ to Entities." exception. I can't seem to find an example on msdn http://msdn.microsoft.com/en-us/library/hh225374(v=vs.110).aspx http://msdn.microsoft.com/en-us/library/hh361035(v=vs.110).aspx And I realize my question is similar to " Entity Framework and Anonymous Types in F# " but it seems to be powerpack/F#2.x focused and I'm hoping F# 3.0 has an elegant answer... Any ideas? UPDATE: I came across the CLIMutable attribute from reading Brian's post at: http://blogs.msdn.com/b/fsharpteam/archive/2012/07/19/more-about-fsharp-3.0-language-features.aspx I was pretty optimistic so I tried [<CLIMutable>] type MyRecord = { Column1 : int; Column2 : int } query { for d in context.table do groupBy {Column1 = col1; Column2 = col2} into g select (g.Key) } Unfortunately I get the exact same exception.

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