A connection between fields in two tables that selects all the records from one table whether or not there are matching records in the other table. When values in the two tables are the same, Microsoft Query combines the matching records and then displays them as one record in the query result set. When a record from the table that's contributing all of its records can't be matched with a record from the other table, the record still appears in the result set. However, the record has empty cells whenever there is no matching record from the other table.