This is the final course in a series that explains how to create select queries in Access 2007. The seventh course showed you how to build multi-source queries. Now we'll show you how to work around an ambiguous outer join, a problem you sometimes have when you create a multi-source query.

Joins become ambiguous when you use more than one join in a query, and the joins are set in a way that doesn't let Access match the records that each join retrieves. To work around the problem, you use separate queries to retrieve data from each join.

Why take this course? Because it teaches you how to work around a common querying problem, and it teaches you how to build a query from another query. That's a valuable skill to have, because you can use it whenever you need to break a complex query into manageable pieces.

To learn more about this course, read the text in Goals and About this course, or look at the table of contents. Then click Next to start the first lesson.

Before you take this course, you need to understand joins, as well as base and secondary tables. You also need to know how to create multi-source queries in Access 2007. If you don't, first take the course listed in the prerequisites, and then come back to this course.

• Queries VII: Query multiple sources for data