blowing up count()

[Dave S]

I have a controller with

 r = db(db.mytable.PostDate is not None)
 streetval = r.count()

which yields a ticket with

<class 'sqlite3.OperationalError'>(near "WHERE": syntax error)[...]Function argument list
(self=<pydal.adapters.sqlite.SQLiteAdapter object>, *a=('SELECT count(*) FROM WHERE 1;',), **b={})
Variables
a	('SELECT count(*) FROM WHERE 1;',)b	{}self	<pydal.adapters.sqlite.SQLiteAdapter object>ret	undefinedcommand	'SELECT count(*) FROM WHERE 1;'self.get_cursor	<bound method SQLiteAdapter.get_cursor of <pydal.adapters.sqlite.SQLiteAdapter object>>).execute	undefined

What did I do wrong?

/dps

[Anthony]

On Monday, January 2, 2017 at 1:36:59 PM UTC-5, Dave S wrote:

I have a controller with

 r = db(db.mytable.PostDate is not None)

The above is not a valid DAL query. It is literally equivalent to:

db(True)

Instead, you must use Python logical operators, as specified in the DAL documentation:

db(db.mytable.PostDate != None)

The presence of the Field object in the above expression overrides the usual behavior of the "!=" operator, returning a DAL Query object rather than a Python boolean value. In your original query, there is no overriding of "is not", so you simply get back a boolean True value (as the Field object itself is not None).

Anthony

[Dave S]

Ah, okay.  I was rushing away from my machine this morning, so I didn't add that a query that checked for equality with req.vars.stuff worked fine.  Your explanation shows why that worked and the above didn't. 

Thanks again !

/dps