private bool CanTranslate(Expression expression)
{
// Check for Query shape
if (IsAggregateGroupBySelector(expression))
{
var groupByResultOperator =
(GroupResultOperator)((SubQueryExpression)((MainFromClause)_groupQuerySource).FromExpression)
.QueryModel.ResultOperators
.Last();
_keySelector = groupByResultOperator.KeySelector;
var elementSelector = groupByResultOperator.ElementSelector;
if (!(elementSelector is QuerySourceReferenceExpression) &&
_sqlTranslatingExpressionVisitorFactory.Create(
_queryModelVisitor,
_selectExpression)
.Visit(groupByResultOperator.ElementSelector) == null)
{
return(false);
}
_selectExpression.ClearOrderBy();
_selectExpression.ClearProjection();
UpdateGroupQuerySourceParameter(typeof(ValueBuffer));
_projectionExpressionVisitor.Visit(_keySelector);
var columns = _selectExpression.Projection.ToArray();
_selectExpression.ClearProjection();
if (!(elementSelector is QuerySourceReferenceExpression))
{
_projectionExpressionVisitor.Visit(groupByResultOperator.ElementSelector);
}
if (_selectExpression.Projection.Count > 1)
{
_selectExpression.ClearProjection();
}
_selectExpression.AddToGroupBy(columns);
var shapedQuery =
(MethodCallExpression)((MethodCallExpression)_queryModelVisitor.Expression).Arguments[0];
var valueBufferShaper = new ValueBufferShaper(_groupQuerySource);
var groupShapedQuery = Expression.Call(
_queryModelVisitor.QueryCompilationContext
.QueryMethodProvider
.ShapedQueryMethod
.MakeGenericMethod(valueBufferShaper.Type),
shapedQuery.Arguments[0],
shapedQuery.Arguments[1],
Expression.Constant(valueBufferShaper));
_queryModelVisitor.Expression = groupShapedQuery;
UpdateGroupQuerySourceParameter(groupShapedQuery.Type);
return(true);
}
return(false);
}