id.max()

[Annet]

In a function I need the id of the last record created in a previous session. I tried:

maxID=db(db.Node).select(db.Node.id.max()).first().id

... but that results in a key error on id.

In a view, this {{=maxID}}, is being rendered as:

<Row {'_extra': <Row {'MAX(Node.id)': 2035}>}>

How do I get maxID=2035


Kind regards,

Annet

[Anthony]

id_max = db.Node.id.max()
maxID = db(db.Node).select(id_max).first()[id_max]

The key used to store the max value is actually the SQL expression generated by the .max() method, so the following should work as well:

maxID = db(db.Node).select(db.Node.id.max()).first()['MAX(Node.id)']

The following explains what is going on: https://groups.google.com/forum/#!msg/web2py/WAw9Z97HJjU/b4XRX2w3xu8J.

For more examples, see http://web2py.com/books/default/chapter/29/6#sum,-min,-max-and-len.

Anthony

[Vasile Ermicioi]

or

max_id = db(db.Node).select(db.Node.id, orderby=~db.Node.id, limitby=(0,1)).first().id

[Annet]

Hi Anthony and Vasile,

Thanks for your replies and explanation, problem solved.

Kind regards,

Annet