I using 3 different tables which are also geographical objects:
- population data; points on the map representing inhabitants (1 or more)
- region data; the map is divided in regions
- coverage data; it contains several coverage areas overlapping or not
What I am searching for is: What is the percentage of people covered by a certain coverage area in a certain region?
I tried several things but nothing worked, for example with SQL select I tried:
Select Columns: Regions.name, CoverageArea.name, Sum(Population.inhabitants)
from Tables: Regions, CoverageArea, Population
where Condition: Regions.obj Contains Population.obj And CoverageArea.obj Contains Population.obj
Group by Columns: 1, 2
Order by Columns: 1, 2
into Table Named: Selection
"And I get Incorrect tables are joined. Invalid join condition in WHERE clause."
Hope I was clear enough :s
** edit **
Few tests I did. I can't understand why the thrid SQL query doesn't work...