protected internal override Expression VisitSelect(SelectExpression select)
{
bool isOuterMost = select == outerMostSelect;
if (select.IsOrderAlsoByKeys || select.HasIndex || select.Top != null && hasProjectionInProjector)
{
if (gatheredKeys == null)
{
gatheredKeys = new List <ColumnExpression>();
}
}
List <ColumnExpression>?savedKeys = null;
if (gatheredKeys != null && (select.IsDistinct || select.GroupBy.HasItems() || select.IsAllAggregates))
{
savedKeys = gatheredKeys.ToList();
}
if ((AggregateFinder.GetAggregates(select.Columns)?.Any(a => a.AggregateFunction.OrderMatters()) ?? false) && select.From is SelectExpression from)
{
var oldOuterMostSelect = outerMostSelect;
outerMostSelect = from;
select = (SelectExpression)base.VisitSelect(select);
outerMostSelect = oldOuterMostSelect;
}
else
{
select = (SelectExpression)base.VisitSelect(select);
}
if (savedKeys != null)
{
gatheredKeys = savedKeys;
}
List <ColumnDeclaration>?newColumns = null;
if (select.GroupBy.HasItems())
{
gatheredOrderings = null;
if (gatheredKeys != null)
{
ColumnGenerator cg = new ColumnGenerator(select.Columns);
var newKeys = new List <ColumnDeclaration>();
foreach (var ge in select.GroupBy)
{
var cd = cg.Columns.NotNull().FirstOrDefault(a => DbExpressionComparer.AreEqual(a.Expression, ge));
if (cd != null)
{
newKeys.Add(cd);
}
else
{
newKeys.Add(cg.NewColumn(ge));
}
}
if (cg.Columns.Count() != select.Columns.Count)
{
newColumns = cg.Columns.NotNull().ToList();
}
gatheredKeys.AddRange(newKeys.Select(cd => new ColumnExpression(cd.Expression.Type, select.Alias, cd.Name)));
}
}
if (select.IsAllAggregates)
{
if (gatheredKeys != null)
{
gatheredKeys.AddRange(select.Columns.Select(cd => new ColumnExpression(cd.Expression.Type, select.Alias, cd.Name)));
}
}
if (select.IsDistinct)
{
gatheredOrderings = null;
if (gatheredKeys != null)
{
gatheredKeys.AddRange(select.Columns.Select(cd => cd.GetReference(select.Alias)));
}
}
if (select.IsReverse && !gatheredOrderings.IsNullOrEmpty())
{
gatheredOrderings = gatheredOrderings.Select(o => new OrderExpression(
o.OrderType == OrderType.Ascending ? OrderType.Descending : OrderType.Ascending,
o.Expression)).ToReadOnly();
}
if (select.OrderBy.Count > 0)
{
this.PrependOrderings(select.OrderBy);
}
ReadOnlyCollection <OrderExpression>?orderings = null;
if (isOuterMost && !IsCountSumOrAvg(select) || select.Top != null)
{
AppendKeys();
orderings = gatheredOrderings;
gatheredOrderings = null;
}
if (AreEqual(select.OrderBy, orderings) && !select.IsReverse && newColumns == null)
{
return(select);
}
return(new SelectExpression(select.Alias, select.IsDistinct, select.Top, (IEnumerable <ColumnDeclaration>?)newColumns ?? select.Columns,
select.From, select.Where, orderings, select.GroupBy, select.SelectOptions & ~SelectOptions.Reverse));
}
public bool Equals(E x, E y)
{
return(DbExpressionComparer.AreEqual(x, y, checkParameterNames: this.checkParameterNames));
}