An outer join in which all the records from the left side of the LEFT JOIN operation in the query's SQL statement are added to the query's results, even if there are no matching values in the joined field from the table on the right. Records from the table on the right are combined with those from the table on the left only when there are matching values in the joined fields.
A left outer join is indicated by a join line arrow (Microsoft Access database) or key symbol (Microsoft Access project) pointing from left to right.