[web2py] Re: How to get the only the value of the Sum in a sum Query?

[Carlos Hanson]

It is probably useful to see the following as well:

>>> sum = db.operations.amount.sum().coalesce_zero()

>>> sum
<gluon.dal.Expression object at 0x12e68d0>
>>> print sum
COALESCE(SUM(operations.amount),0)

>>> monthly_amount_first = db((db.operations.date.year()==current_year) & 
...                           (db.operations.date.month()==current_month)
...                          ).select(sum).first()
>>> monthly_amount_first
<Row {'_extra': <Row {'COALESCE(SUM(operations.amount),0)': 45.0}>}>
>>> monthly_amount_first[sum]
45.0