public static bool HasAggregates(DbSelectExpression expression)
{
var checker = new DbAggregateChecker();
if (checker != null)
{
checker.Visit(expression);
}
return(checker.hasAggregate);
}
private bool CanJoinOnClient(DbSelectExpression select)
{
return
(
this.canJoinOnClient &&
this.currentMember != null &&
!this.policy.IsDeferLoaded(this.currentMember) &&
!select.IsDistinct &&
(select.GroupBy == null || select.GroupBy.Count == 0) &&
!DbAggregateChecker.HasAggregates(select)
);
}
private bool CanJoinOnServer(DbSelectExpression select)
{
return(select.IsDistinct == false && (select.GroupBy == null || select.GroupBy.Count == 0) && !DbAggregateChecker.HasAggregates(select));
}
protected override Expression VisitSelect(DbSelectExpression select)
{
bool saveIsOuterMostSelect = this.isOuterMostSelect;
try
{
this.isOuterMostSelect = false;
select = base.VisitSelect(select) as DbSelectExpression;
var hasOrderBy = select.OrderBy != null && select.OrderBy.Count > 0;
var hasGroupBy = select.GroupBy != null && select.GroupBy.Count > 0;
var canHaveOrderBy = saveIsOuterMostSelect || select.Take != null || select.Skip != null;
var canReceiveOrderings = canHaveOrderBy && !hasGroupBy && !select.IsDistinct && !DbAggregateChecker.HasAggregates(select);
if (hasOrderBy)
{
this.PrependOrderings(select.OrderBy);
}
if (select.IsReverse)
{
this.ReverseOrderings();
}
var orderings = null as IEnumerable <DbOrderExpression>;
if (canReceiveOrderings)
{
orderings = this.gatheredOrderings;
}
else if (canHaveOrderBy)
{
orderings = select.OrderBy;
}
var canPassOnOrderings = !saveIsOuterMostSelect && !hasGroupBy && !select.IsDistinct;
var columns = select.Columns;
if (this.gatheredOrderings != null)
{
if (canPassOnOrderings)
{
var producedAliases = DbDeclaredAliasGatherer.Gather(select.From);
var project = this.RebindOrderings(this.gatheredOrderings, select.Alias, producedAliases, select.Columns);
this.gatheredOrderings = null;
this.PrependOrderings(project.Orderings);
columns = project.Columns;
}
else
{
this.gatheredOrderings = null;
}
}
if (orderings != select.OrderBy || columns != select.Columns || select.IsReverse)
{
select = new DbSelectExpression(select.Alias, columns, select.From, select.Where, orderings, select.GroupBy, select.IsDistinct, select.Skip, select.Take, false);
}
return(select);
}
finally
{
this.isOuterMostSelect = saveIsOuterMostSelect;
}
}
protected override Expression VisitJoin(DbJoinExpression join)
{
join = base.VisitJoin(join) as DbJoinExpression;
if (join.JoinType == JoinType.CrossApply || join.JoinType == JoinType.OuterApply)
{
if (join.Right is DbTableExpression)
{
return(new DbJoinExpression(JoinType.CrossJoin, join.Left, join.Right, null));
}
if (join.Right is DbSelectExpression select && select.Take == null && select.Skip == null && !DbAggregateChecker.HasAggregates(select) && (select.GroupBy == null || select.GroupBy.Count == 0))
{
var selectWithoutWhere = select.SetWhere(null);
var referencedAliases = DbReferencedAliasGatherer.Gather(selectWithoutWhere);
var declaredAliases = DbDeclaredAliasGatherer.Gather(join.Left);
if (referencedAliases != null)
{
referencedAliases.IntersectWith(declaredAliases);
}
if (referencedAliases.Count == 0)
{
var where = select.Where;
select = selectWithoutWhere;
var pc = DbColumnProjector.ProjectColumns(this.language, where, select.Columns, select.Alias, DbDeclaredAliasGatherer.Gather(select.From));
select = select.SetColumns(pc.Columns);
where = pc.Projector;
var jt = (where == null) ? JoinType.CrossJoin : (join.JoinType == JoinType.CrossApply ? JoinType.InnerJoin : JoinType.LeftOuter);
return(new DbJoinExpression(jt, join.Left, select, where));
}
}
}
return(join);
}
private static bool CanMergeWithFrom(DbSelectExpression select, bool isTopLevel)
{
var fromSelect = GetLeftMostSelect(select.From);
if (fromSelect == null)
{
return(false);
}
if (IsColumnProjection(fromSelect) == false)
{
return(false);
}
var selHasNameMapProjection = IsNameMapProjection(select);
var selHasOrderBy = select.OrderBy != null && select.OrderBy.Count > 0;
var selHasGroupBy = select.GroupBy != null && select.GroupBy.Count > 0;
var selHasAggregates = DbAggregateChecker.HasAggregates(select);
var selHasJoin = select.From is DbJoinExpression;
var frmHasOrderBy = fromSelect.OrderBy != null && fromSelect.OrderBy.Count > 0;
var frmHasGroupBy = fromSelect.GroupBy != null && fromSelect.GroupBy.Count > 0;
var frmHasAggregates = DbAggregateChecker.HasAggregates(fromSelect);
if (selHasOrderBy && frmHasOrderBy)
{
return(false);
}
if (selHasGroupBy && frmHasGroupBy)
{
return(false);
}
if (select.IsReverse || fromSelect.IsReverse)
{
return(false);
}
if (frmHasOrderBy && (selHasGroupBy || selHasAggregates || select.IsDistinct))
{
return(false);
}
if (frmHasGroupBy)
{
return(false);
}
if (fromSelect.Take != null && (select.Take != null || select.Skip != null || select.IsDistinct || selHasAggregates || selHasGroupBy || selHasJoin))
{
return(false);
}
if (fromSelect.Skip != null && (select.Skip != null || select.IsDistinct || selHasAggregates || selHasGroupBy || selHasJoin))
{
return(false);
}
if (fromSelect.IsDistinct && (select.Take != null || select.Skip != null || !selHasNameMapProjection || selHasGroupBy || selHasAggregates || (selHasOrderBy && !isTopLevel) || selHasJoin))
{
return(false);
}
if (frmHasAggregates && (select.Take != null || select.Skip != null || select.IsDistinct || selHasAggregates || selHasGroupBy || selHasJoin))
{
return(false);
}
return(true);
}
