Please open a ticket about this. Expressions like date_diff were designed to be in the query, not in the list of selected columns. I think this can be done but need to check what breaks.
On Friday, 28 June 2013 03:02:06 UTC-5, Paolo valleri wrote: > > Dear all, > I am trying to run simple mathematical operations with datetime and > postgres as backend ( > http://www.postgresql.org/docs/9.0/static/functions-datetime.html) > I've prepared this simple example code: > from datetime import timedelta > db.define_table('test_sum', > Field('first_int', 'integer'), > Field('second_int', 'integer'), > Field('first_date', 'datetime'), > Field('second_date', 'datetime'), > ) > > db.test_sum.insert(first_int=40, second_int=30, first_date=request.now, > second_date=request.now-timedelta(days=1)) > diff_int = db.test_sum.first_int - db.test_sum.second_int > diff_date = db.test_sum.first_date - db.test_sum.second_date > print db(db.test_sum).select(diff_int) > print db(db.test_sum).select(diff_date) > With postgres the first query is executed correctly, the second failed > raising the ticket: > > Traceback (most recent call last): > File "/home/pvalleri/src/web2py/gluon/restricted.py", line 212, in > restricted > exec ccode in environment > File "/home/pvalleri/src/web2py/applications/vtraffic/models/db.py" > <http://127.0.0.1:8000/admin/edit/vtraffic/models/db.py>, line 98, in <module> > print db(db.test_sum).select(diff_date) > File "/home/pvalleri/src/web2py/gluon/dal.py", line 9935, in select > return adapter.select(self.query,fields,attributes) > File "/home/pvalleri/src/web2py/gluon/dal.py", line 1709, in select > return self._select_aux(sql,fields,attributes) > File "/home/pvalleri/src/web2py/gluon/dal.py", line 1690, in _select_aux > return processor(rows,fields,self._colnames,cacheable=cacheable) > File "/home/pvalleri/src/web2py/gluon/dal.py", line 2093, in parse > fields[j].type,blob_decode) > File "/home/pvalleri/src/web2py/gluon/dal.py", line 1908, in parse_value > return self.parsemap[key](value,field_type) > File "/home/pvalleri/src/web2py/gluon/dal.py", line 1995, in parse_double > return float(value) > TypeError: float() argument must be a string or a number > > > To some extent the interesting ticket is that, the query generated works > without problems (tested with pgadmin). > SELECT (test_sum.second_date - test_sum.first_date) FROM test_sum WHERE ( > test_sum.id IS NOT NULL); > > Moreover, I run the same example with sqlite, it worked well without > error, the resulting values are wrong though. > What can I do? > > Paolo > > -- --- You received this message because you are subscribed to the Google Groups "web2py-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/groups/opt_out.
