Я нашел ответ:
Dim query = From final In _
(From lh In Me.AnnualCost1.sp_annualcostLH _
Group lh By lh.Asset_Number Into Group) _
Let Jan As Object = (From r In final.Group Where _
r.Month = "January" _
Select r.lhTotal).Sum _
Select New With { _
.Asset_Number = final.Asset_Number, _
.January = If(Jan Is Nothing, 0, Jan) _
}
Это создает сводную таблицу со столбцом по месяцам. Вот только за январь
Julien