Why does Access make mistakes when counting?

[Guest]

I am running a query in which I am asking Access to count the number of
events linked to individuals in a particular month.

Each individual and crime has a unique number. The query is based on three
tables linked together: the details of the people, the details of the crimes
and the links between them.

When I ask the file to count the number of events for a particular
individual, it tells me that there are 23. When I change the command to
"Group By" to list the events with their particular identification numbers,
there are 11. Having run other checks, it is clear that 11 is the correct
number. The same thing has happened for other individuals and is the same
with unique value and unique records set to yes. I cannot see any
predictable relationship between the right and wrong numbers.

Why is Access counting wrong?

 

[ChrisM]

Hi Richard,

Would you like to show us the queries that you are running, and an example
of the data that is giving these results?
My guess is that in linking the tables, you are not linking unique keys
correctly, and aregenerating more rows than you should have.

Cheers,

Chris.

 

[Guest]

Its OK I have now worked out where the problem is!

 

[ChrisM]

Out of interest, what was it?