Any idea why the below does not work? EndDate is a nullable datetime field, so it wouldn't let me attach the AddMinutes method directly to it, I had to use GetValueOrDefault in between. It gives the error message shown below. Note that if EndDate is not nullable then it works fine as s.EndDate.AddMinutes. FYI I also tried using s.EndDate.GetValueOrDefault(someDate).AddMinutes but that gave the same error.

Adapter method, ORMSupportClasses 3.1.11.0527, LinqSupportClasses 3.1.11.0518, SQL Server2005

    Public Shared Function GetSubscriptionsToRenew(ByVal pRenewalLeadTime As TimeSpan) As List(Of SubscriptionEntity)
        'Get the timespan in minutes and negate it, since we subtracting this quantity from the subscription's end date
        Dim renewalLeadTimeMinutes As Double = -pRenewalLeadTime.TotalMinutes

        Dim linqMeta As New LinqMetaData(DataAdapter)


        Dim q = _
         (From s In linqMeta.Subscription _
         Where s.IsActive = True _
         AndAlso s.IsAutoRenew = True _
         AndAlso s.EndDate.GetValueOrDefault.AddMinutes(renewalLeadTimeMinutes) < DateTime.Now _
         Select s)

        Return q.ToList
    End Function

This produces the following expression:

: Initial expression to process:
value(SD.LLBLGen.Pro.LinqSupportClasses.DataSource2`1[PSE.Web.Model.EntityClasses.SubscriptionEntity]).Where(s => (((s.IsActive == True) AndAlso (s.IsAutoRenew == True)) AndAlso (s.EndDate.GetValueOrDefault().AddMinutes(value(PSE.Web.BLL.SubscriptionRepository+_Closure$__21).$VB$Local_renewalLeadTimeMinutes) < DateTime.Now))).Select(s => s)

Error message and stack trace:

A first chance exception of type 'SD.LLBLGen.Pro.ORMSupportClasses.ORMQueryConstructionException' occurred in SD.LLBLGen.Pro.LinqSupportClasses.NET35.dll
System.Transactions Critical: 0 : <TraceRecord xmlns="http://schemas.microsoft.com/2004/10/E2ETraceEvent/TraceRecord" Severity="Critical"><TraceIdentifier>http://msdn.microsoft.com/TraceCodes/System/ActivityTracing/2004/07/Reliability/Exception/Unhandled</TraceIdentifier><Description>Unhandled exception</Description><AppDomain>PSE.Web.PeriodicBilling.exe</AppDomain><Exception><ExceptionType>SD.LLBLGen.Pro.ORMSupportClasses.ORMQueryConstructionException, SD.LLBLGen.Pro.ORMSupportClasses.NET20, Version=3.1.0.0, Culture=neutral, PublicKeyToken=ca73b74ba4e3ff27</ExceptionType><Message>The parameter at position 0 is of an unsupported type: Call</Message><StackTrace>   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleDbFunctionCallExpression(DbFunctionCallExpression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 1401
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.GenericExpressionHandler.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\GenericExpressionHandler.cs:line 146
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 141
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleBinaryExpressionBooleanOperator(BinaryExpression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 2045
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.GenericExpressionHandler.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\GenericExpressionHandler.cs:line 271
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 141
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleBinaryExpressionBooleanOperator(BinaryExpression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 2046
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.GenericExpressionHandler.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\GenericExpressionHandler.cs:line 271
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 141
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleLambdaExpression(LambdaExpression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 2703
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.GenericExpressionHandler.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\GenericExpressionHandler.cs:line 296
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 141
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleWhereExpression(WhereExpression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 1441
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.GenericExpressionHandler.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\GenericExpressionHandler.cs:line 216
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 141
   at SD.LLBLGen.Pro.LinqSupportClasses.LLBLGenProProviderBase.HandleExpressionTree(Expression expression) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\LLBLGenProProviderBase.cs:line 158
   at SD.LLBLGen.Pro.LinqSupportClasses.LLBLGenProProviderBase.Execute(Expression expression) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\LLBLGenProProviderBase.cs:line 92
   at SD.LLBLGen.Pro.LinqSupportClasses.LLBLGenProProviderBase.System.Linq.IQueryProvider.Execute(Expression expression) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\LLBLGenProProviderBase.cs:line 697
   at SD.LLBLGen.Pro.LinqSupportClasses.LLBLGenProQuery`1.Execute() in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\LLBLGenProQuery.cs:line 87
   at SD.LLBLGen.Pro.LinqSupportClasses.LLBLGenProQuery`1.System.Collections.Generic.IEnumerable&amp;lt;T&amp;gt;.GetEnumerator() in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\LLBLGenProQuery.cs:line 162
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at PSE.Web.BLL.SubscriptionRepository.GetSubscriptionsToRenew(TimeSpan pRenewalLeadTime) in SubscriptionRepository.vb:line 136
   at PSE.Web.BLL.SubscriptionManagementService.GetSubscriptionsToRenew(TimeSpan pRenewalLeadTime) in SubscriptionManagementService.vb:line 325
   at PSE.Web.PeriodicBilling.Main.Main() in Main.vb:line 21</StackTrace><ExceptionString>SD.LLBLGen.Pro.ORMSupportClasses.ORMQueryConstructionException: The parameter at position 0 is of an unsupported type: Call
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleDbFunctionCallExpression(DbFunctionCallExpression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 1401
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.GenericExpressionHandler.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\GenericExpressionHandler.cs:line 146
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 141
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleBinaryExpressionBooleanOperator(BinaryExpression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 2045
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.GenericExpressionHandler.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\GenericExpressionHandler.cs:line 271
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 141
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleBinaryExpressionBooleanOperator(BinaryExpression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 2046
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.GenericExpressionHandler.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\GenericExpressionHandler.cs:line 271
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 141
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleLambdaExpression(LambdaExpression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 2703
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.GenericExpressionHandler.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\GenericExpressionHandler.cs:line 296
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 141
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleWhereExpression(WhereExpression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 1441
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.GenericExpressionHandler.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\GenericExpressionHandler.cs:line 216
   at SD.LLBLGen.Pro.LinqSupportClasses.ExpressionHandlers.QueryExpressionBuilder.HandleExpression(Expression expressionToHandle) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\ExpressionHandlers\QueryExpressionBuilder.cs:line 141
   at SD.LLBLGen.Pro.LinqSupportClasses.LLBLGenProProviderBase.HandleExpressionTree(Expression expression) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\LLBLGenProProviderBase.cs:line 158
   at SD.LLBLGen.Pro.LinqSupportClasses.LLBLGenProProviderBase.Execute(Expression expression) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\LLBLGenProProviderBase.cs:line 92
   at SD.LLBLGen.Pro.LinqSupportClasses.LLBLGenProProviderBase.System.Linq.IQueryProvider.Execute(Expression expression) in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\LLBLGenProProviderBase.cs:line 697
   at SD.LLBLGen.Pro.LinqSupportClasses.LLBLGenProQuery`1.Execute() in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\LLBLGenProQuery.cs:line 87
   at SD.LLBLGen.Pro.LinqSupportClasses.LLBLGenProQuery`1.System.Collections.Generic.IEnumerable&amp;lt;T&amp;gt;.GetEnumerator() in c:\Myprojects\VS.NET Projects\LLBLGen Pro v3.1\Frameworks\LLBLGen Pro\RuntimeLibraries\LinqSupportClasses\LLBLGenProQuery.cs:line 162
   at System.Collections.Generic.List`1..ctor(IEnumerable`1 collection)
   at System.Linq.Enumerable.ToList[TSource](IEnumerable`1 source)
   at PSE.Web.BLL.SubscriptionRepository.GetSubscriptionsToRenew(TimeSpan pRenewalLeadTime) in SubscriptionRepository.vb:line 136
   at PSE.Web.BLL.SubscriptionManagementService.GetSubscriptionsToRenew(TimeSpan pRenewalLeadTime) in SubscriptionManagementService.vb:line 325
   at PSE.Web.PeriodicBilling.Main.Main() in Main.vb:line 21</ExceptionString></Exception></TraceRecord>

Use the .Value property. For example:

var q = from o in metaData.Order
    where o.OrderDate.Value.AddYears(14) > DateTime.Now
    select o;

Won't this crash if the value is null?

pt wrote:

Won't this crash if the value is null?

No.

It's just for the evaluation tree to compile. For instance this code:

var q = (from po in metaData.PurchaseOrder
            where po.ShipDate.Value.AddDays(8) < DateTime.Now
            select po).ToList();

generates this sql:

SELECT ...   
WHERE ( ( ( ( DATEADD(dd, @p4, [LPA_L1].[ShipDate]) < @p2))))
    Parameter: @p4 : Double. Length: 0. Precision: 0. Scale: 0. Direction: Input. Value: 8.
    Parameter: @p2 : DateTime. Length: 0. Precision: 0. Scale: 0. Direction: Input. Value: 6/17/2011 2:39:32 PM.