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);
}