Microsoft Office Tutorials and References
In Depth Information
Joining tables to see unmatched or missing records
Joining tables to see unmatched or missing records
In “Join multiple tables” on page 99, we saw how to join more
than one table on a query. Tables can be joined in one of three
ways. The method of joining is shown on the diagram, with
either no arrow or an arrow at one or the other end of the join.
When you click the join, you will see a text description of how
each choice will affect the data.
There are two classic uses of changing the join. The first allows
you to identify unmatched child records (which can prevent you
from creating relationships that enforce rule checking), and the
second is useful when you appear to have missing records in the
query results.
Find unmatched child records
1 Double-click the relationship.
2 In the Join Properties popup window, click the option to include all
child records. (In this case, the Orders table is a child of the
Customers table.) This will now show all orders, whether or not there is a
customer in the Customers table for the corresponding ID recorded
in the Orders table. Click OK to close the Join Properties popup
3 Add criteria to identify where the parent key (ID in Customers
table) has no value (Is Null). This filters the query results to show
only those records in the Orders table where there are no matching
customers in the Customers table.
TIP On the Create tab, you can create this type of query by
using the Query Wizard, which will display a Find Unmatched
Query option.
Search JabSto ::

Custom Search