This is SQL language. I'm far from an expert and do more trial and error joining in QB then I would like to admit but from what I do know is that the Outter Join is a bit more flexible than the inner join as it has less requirements on it. I copied some Wiki info below:
Reference
outer join
The result of a left outer join (or simply left join) for table A and B always contains all records of the "left" table (A), even if the join-condition does not find any matching record in the "right" table (B). This means that if the ON clause matches 0 (zero) records in B, the join will still return a row in the result-but with NULL in each column from B. This means that a left outer join returns all the values from the left table, plus matched values from the right table (or NULL in case of no matching join predicate). If the right table returns one row and the left table returns more than one matching row for it, the values in the right table will be repeated for each distinct row on the left table. From Oracle 9i onwards the LEFT OUTER JOIN statement can be used as well as (+).[5]<
">http://en.wikipedia.org/wiki/Join_(SQL)#cite_note-4>For example, this allows us to find an employee's department, but still shows the employee(s) even when they have not been assigned to a department (contrary to the inner-join example above, where unassigned employees are excluded from the result).
Example of a left outer join, with the additional result row italicized:
SELECT *
FROM employee
LEFT OUTER JOIN department ON employee.DepartmentID = department.DepartmentID;
Employee.LastName
Employee.DepartmentID
Department.DepartmentName
Department.DepartmentID
Jones
33
Engineering
33
Rafferty
31
Sales
31
Robinson
34
Clerical
34
Smith
34
Clerical
34
John
NULL
NULL
NULL
Steinberg
33
Engineering
33
Oracle supports the alternate syntax:
SELECT * FROM employee, department WHERE employee.DepartmentID = department.DepartmentID(+)
Sybase supports the alternate syntax:
SELECT * FROM employee, department WHERE employee.DepartmentID *= department.DepartmentID
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Steve Vinyard
Application Engineer