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Queries VIII: Dealing with ambiguous joins

Learn how to work around ambiguous joins
Learn how to resolve ambiguous outer joins. When you build a multi-source query, you sometimes get an error message that says you have an "ambiguous outer join." This course explains that type of join, and how to build queries that work around it.

About this course

This course includes:

  • One self-paced lesson and one practice session for hands-on experience. The practice requires Access 2007.
  • A short test at the end of the lesson; the test is not scored.
  • A Quick Reference Card you can take away from the course.


After completing this course you will be able to:

  • Create queries that work around ambiguous outer joins.
  • Build queries that use two or more queries as data sources.

Before you begin

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.

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.

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