[GRASSLIST:4338] v.to.db

[Leonardo Lami]

Hi,
I'd like to know if is it possible and how make this kind of operation in 
Grass.
I have a vector linked to a table with this three fields: id, count, area, 
value and I'd like to update the field "value" with the result of this 
operation: "count" value / "area" value

I tried to use v.to.db:
v.to.db map=g_anfibi field=3 qfield=3 option=query col1=sum qcol="count/area"
but the output message say:
Reading data trom the map ...  100%
Querying database ... DBMI-DBF driver error:
SQL parser error in statement:
SELECT sum(valore) FROM g_anfibi WHERE cat = 1
Error in db_open_select_cursor()


I tried also:
echo "UPDATE g_anfibi_sum SET sum=count/area" | db.execute
but the output message say:
DBMI-DBF driver error:
SQL parser error in statement:
UPDATE g_anfibi_sum SET sum=count/area
Error in db_execute_immediate()
WARNING: Error while executing: "UPDATE g_anfibi_sum SET sum=count/area

Which is the best solution?

Thanks
-- 
Leonardo Lami
lami at faunalia.it            www.faunalia.it
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