public override IASTNode VisitTableFactor(SqlServerCommandParser.TableFactorContext context)
        {
            TableFactorSegment result = new TableFactorSegment();

            if (null != context.subquery())
            {
                var subquery             = (SelectCommand)Visit(context.subquery());
                var subquerySegment      = new SubQuerySegment(context.subquery().Start.StartIndex, context.subquery().Stop.StopIndex, subquery);
                var subqueryTableSegment = new SubQueryTableSegment(subquerySegment);
                if (null != context.alias())
                {
                    subqueryTableSegment.SetAlias((AliasSegment)Visit(context.alias()));
                }
                result.SetTable(subqueryTableSegment);
            }
            if (null != context.tableName())
            {
                SimpleTableSegment table = (SimpleTableSegment)Visit(context.tableName());
                if (null != context.alias())
                {
                    table.SetAlias((AliasSegment)Visit(context.alias()));
                }
                result.SetTable(table);
            }
            if (null != context.tableReferences())
            {
                var tableReferences = (CollectionValue <TableReferenceSegment>)Visit(context.tableReferences());
                result.TableReferences.AddAll(tableReferences.GetValue());
            }
            return(result);
        }
        public override IASTNode VisitSingleTableClause(SqlServerCommandParser.SingleTableClauseContext context)
        {
            SimpleTableSegment result = (SimpleTableSegment)Visit(context.tableName());

            if (null != context.alias())
            {
                result.SetAlias((AliasSegment)Visit(context.alias()));
            }
            return(result);
        }