db.select() is a helper function for simple 'select' statements. For this
you'll want to use the more flexible db.query(). See
http://webpy.org/cookbook/query for a pretty good explanation.
db.query("SELECT city FROM weather WHERE temp_lo = (SELECT
max(temp_lo) FROM weather)")
On Mon, Jul 15, 2013 at 2:43 PM, Claudio Dusan Vega Ozuljevich <
[email protected]> wrote:
> What I needed is to know how to implement it in python and web.py. If
> i got this:
>
> db.select('myTable', where='column1=$value', vars={'value':value})
>
> but need to do another select inside this one, how can I do it?
>
>
> On Mon, Jul 15, 2013 at 2:35 PM, Shannon Cruey
> <[email protected]> wrote:
> > I'm using MySql and not Postgres, but your example is actually a valid
> query
> > and should work. Whenever possible and practical (as in this case), you
> > should use native sql functions instead of local python functions.
> >
> > Using max() INSIDE the query puts the workload on the server, which is
> > exactly what it's tuned to do very efficiently. Pulling back a whole
> > recordset and looking for the max, or doing two queries, brings the
> workload
> > to you, which is far more inefficient.
> >
> > Are you seeing an error with this query?
> >
> >
> >
> > On Mon, Jul 15, 2013 at 1:34 PM, Claudio Dusan Vega Ozuljevich
> > <[email protected]> wrote:
> >>
> >> Hi guys, I need to know how to perform a query like this one:
> >>
> >> SELECT city FROM weather
> >> WHERE temp_lo = (SELECT max(temp_lo) FROM weather);
> >>
> >> As you can see is a Select nested inside another Select,
> >>
> >> In addition, is it possible to use the postgresql fuction (in this
> >> case max()) from web.py, or do I need to use another python module, in
> >> that case, which one do you recommend?
> >>
> >> Thanks in advance.
> >>
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