public override DbExpression Visit(DbGroupByExpression expression)
{
Check.NotNull(expression, "expression");
DbExpression result = expression;
var newInput = VisitGroupExpressionBinding(expression.Input);
EnterScope(newInput.Variable);
var newKeys = VisitExpressionList(expression.Keys);
ExitScope();
EnterScope(newInput.GroupVariable);
var newAggs = VisitList(expression.Aggregates, VisitAggregate);
ExitScope();
if (!ReferenceEquals(expression.Input, newInput)
||
!ReferenceEquals(expression.Keys, newKeys)
||
!ReferenceEquals(expression.Aggregates, newAggs))
{
var groupOutput =
TypeHelpers.GetEdmType <RowType>(TypeHelpers.GetEdmType <CollectionType>(expression.ResultType).TypeUsage);
var boundKeys = groupOutput.Properties.Take(newKeys.Count).Select(p => p.Name).Zip(newKeys).ToList();
var boundAggs = groupOutput.Properties.Skip(newKeys.Count).Select(p => p.Name).Zip(newAggs).ToList();
result = CqtBuilder.GroupBy(newInput, boundKeys, boundAggs);
}
NotifyIfChanged(expression, result);
return(result);
}