Question

i am fooling around with the new entity framework, and just for fun io wanted to convert all exsiting querys om a old site to new and shinny linq. But i cant really figure this query out. The smallest help would be awsome.

the query i try to convert.. could handle the foreach in my c# code now so if it is leave that out, it is more the nested selects and IN that is bugging me

DECLARE @Begin DateTime, @End DateTime, @date DateTime, @partnerId int

Set @partnerId = 1
Set @Begin = Cast('2010-01-01' as DateTime)
Set @End = Cast(Dateadd(month, 17, @Begin) as DateTime)
Set @date = @Begin

SET NOCOUNT ON
WHILE (@date <= @End)
BEGIN
    SELECT
        [PackageId],
        @date AS [Date],
        [Name],
        (ISNULL((SELECT [ReportId] FROM [Uniferon_Reports] WHERE [FK_PartnerId] = @partnerId AND [FK_PackageId] = [Uniferon_Packages].[PackageId] AND [Date] = @date), 0)) AS [ReportId],
        (ISNULL((SELECT [UnitsForecast] FROM [Uniferon_Reports] WHERE [FK_PartnerId] = @partnerId AND [FK_PackageId] = [Uniferon_Packages].[PackageId] AND [Date] = @date), 0)) AS [UnitsForecast],
        (ISNULL((SELECT [UnitsActual] FROM [Uniferon_Reports] WHERE [FK_PartnerId] = @partnerId AND [FK_PackageId] = [Uniferon_Packages].[PackageId] AND [Date] = @date), 0)) AS [UnitsActual],
        (ISNULL((SELECT [RevenueForecast] FROM [Uniferon_Reports] WHERE [FK_PartnerId] = @partnerId AND [FK_PackageId] = [Uniferon_Packages].[PackageId] AND [Date] = @date), 0)) AS [RevenueForecast],
        (ISNULL((SELECT [RevenueActual] FROM [Uniferon_Reports] WHERE [FK_PartnerId] = @partnerId AND [FK_PackageId] = [Uniferon_Packages].[PackageId] AND [Date] = @date), 0)) AS [RevenueActual],
        (ISNULL((SELECT [UnitsInStock] FROM [Uniferon_Reports] WHERE [FK_PartnerId] = @partnerId AND [FK_PackageId] = [Uniferon_Packages].[PackageId] AND [Date] = @date), 0)) AS [UnitsInStock]
        FROM
            [Uniferon_Packages][Uniferon_Packages]
        WHERE
        [PackageId] IN 
        (SELECT [FK_PackageId] FROM [Uniferon_Partners_Packages_Relation] WHERE [FK_PartnerId] = @partnerId AND [StartDate] <= @date    AND ([EndDate] >= @date OR [EndDate] IS NULL))


Set @date = DateAdd(month, 1, @date)
END
SET NOCOUNT OFF   

any thoughts ?

Answer 1

Something like this. Hope this will help you to understand LINQ more effective 😉 :

while (date <= endDate)
{
    var result = Uniferon_Packages
        .Where(i => 
            Uniferon_Partners_Packages_Relation.Any(rel => rel.FK_PartnerId == i.PackageId) &&
            rel.StartDate <= date && (!rel.EndDate.HasValue || rel.EndDate >= date))
        .Select(i => new
                         {
                             i.PackageId,
                             i.Name,
                             Date = date,
                             ReportId = GetReportId(i, partnerId, date)
                             // etc...
                         });

    date = date.AddMonths(1);
}


private int GetReportId(Uniferon_Package pack, int partnerId, DateTime date)
{
    var report = Uniferon_Reports.FirstOrDefault(x => 
        x.FK_PartnerId == partnerId && 
        x.FK_PackageId == pack.PackageId && 
        x.Date == date);

    return report != null
        ? report.ReportId
        : 0;
}