Queries and Subqueries

[Guest]

I have been trying to find a solution to a problem I am having getting the
correct records into a report without duplicate reports....

I've come across some information on Queries and subqueries and am curious
as to how these work and what purpose they serve. What kinds of scenarios
does it work well to use a query/subquery? Could I use it to exclude data
from a table so that duplicate records are not displayed??

Is there another way to exclude data from report using a query?

Thanks for any ideas or information!

 

[Allen Browne]

For an introduction, see:
How to Create and Use Subqueries
at:
http://support.microsoft.com/?id=209066

Some uses for subqueries:
- to retrieve one value from one column of a related table
(including getting the latest value, or a count of values);
- to find out if a related value exists in another table;
- to filter by a value in another table.

Some limitations of subqueries:
- Query is read-only if you display the result of the subquery.
- Reports may struggle with "multi-level group by not allowed".
- It's not difficult to crash JET by stacking more things on top of
subqueries.