Exemple #1
0
            private SqlJoin GetLeftOuterWithUnreferencedSingletonOnLeft(SqlSource source)
            {
                SqlAlias alias = source as SqlAlias;

                if (alias != null)
                {
                    SqlSelect select = alias.Node as SqlSelect;
                    if (select != null &&
                        select.Where == null &&
                        select.Top == null &&
                        select.GroupBy.Count == 0 &&
                        select.OrderBy.Count == 0)
                    {
                        return(this.GetLeftOuterWithUnreferencedSingletonOnLeft(select.From));
                    }
                }
                SqlJoin join = source as SqlJoin;

                if (join == null || join.JoinType != SqlJoinType.LeftOuter)
                {
                    return(null);
                }
                if (!this.IsSingletonSelect(join.Left))
                {
                    return(null);
                }
                HashSet <SqlAlias> p = SqlGatherProducedAliases.Gather(join.Left);
                HashSet <SqlAlias> c = SqlGatherConsumedAliases.Gather(join.Right);

                if (p.Overlaps(c))
                {
                    return(null);
                }
                return(join);
            }
Exemple #2
0
            internal override SqlSource VisitJoin(SqlJoin join)
            {
                if (join.JoinType == SqlJoinType.CrossApply)
                {
                    // Look down the left side to see what table aliases are produced.
                    HashSet <SqlAlias> p = SqlGatherProducedAliases.Gather(join.Left);
                    // Look down the right side to see what table aliases are consumed.
                    HashSet <SqlAlias> c = SqlGatherConsumedAliases.Gather(join.Right);
                    // Look at each consumed alias and see if they are mentioned in produced.
                    if (p.Overlaps(c))
                    {
                        Annotations.Add(join, new SqlServerCompatibilityAnnotation(Strings.SourceExpressionAnnotation(join.SourceExpression), SqlProvider.ProviderMode.Sql2000));
                        // Can't reduce because this consumed alias is produced on the left.
                        return(base.VisitJoin(join));
                    }

                    // Can turn this into a CROSS JOIN
                    join.JoinType = SqlJoinType.Cross;
                    return(VisitJoin(join));
                }
                return(base.VisitJoin(join));
            }