[AccessD] complex query!!

On Wed, Jan 12, 2005 at 01:51:38PM +0100, Pedro Janssen wrote:
> Hello group,
> 
> for a statistic analyses of DNA-samples i need to compare each sample from a group with eachother sample from another group. I have 7 groups with up to 17 samples. Let me explain what i need in an example. 
> 
> I have
> 
> Two tables group1 and group2, with each two records.
> 
> 
> i need the average of:
> group1_record1 + group2_record1
> group1_record2 + group2_record1
> group1_record1 + group2_record2
> group1_record2 + group2_record2
> 
> 
> and this for 7 groups up to 17 records
> 
> 
> Is this possible in a query per 2 groups, 
> or can this been done in total by code?

Pedro, your example is a little ambiguous. Assuming that you want to add
records and take the average, and not add columns and take the average,
the query is a simple Cartesian product. Assuming a column in group1
named First and a column in group2 named Second:

SELECT Avg(group1.First + group2.Second) AS Mean
>From group1, group2;

If you had tables with thousands of records, this would take forever to
run. But as long as you've got less than 100 records in each table, it
should be OK.

I apologize if I misunderstand what you're trying to do.

Bob Hall