Hi list,

 

I'm doing some population density calculations using the SQL Select
tool.  I have population data and area data for several hundred regions
in a table.  In order to get the aggregate density for the total area,
I'm summing these two fields in a query and manually dividing total
population by total area.  My issue is that MapInfo allows me to define
two separate columns using the sum(*) function, but when I try to define
a single density field, which looks something like this:

 

Sum(population)/Sum(Area) "Density"

 

It doesn't work.  "Found[/] while searching for [A string constant]" is
the error I get.  Interestingly, the following custom fields do work:

 

Population/Area - returns the density of each region in the table

 

Sum(Population/Area) - returns the sum of all regions' density, which is
meaningless.

 

I don't want a MapBasic solution, I would just like someone to confirm
that what I'm trying to do is not allowed, or let me know if there is a
way.  This problem isn't keeping me from doing my work, I'm just
surprised that this functionality isn't available and want to test my
findings with the list.  Using MapInfo Pro 6.5

 

Lawson Key

CenturyTel

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