[storm] Problem with EXISTS clause

[Edoardo Serra]

Hi guys,
	I have some problems in building a query using the EXISTS clause.

I have two tables:

CREATE TABLE accounts (
    id serial NOT NULL,
    legal_name character varying(255) NOT NULL,
    address_1 character varying(255),
    ...
);

CREATE TABLE subscriptions (
    id serial NOT NULL,
    account_id integer NOT NULL,
    date_start date NOT NULL,
    ...
);

I would like to know how many accounts are not subscribed to any service.

The SQL query to get that should be:

SELECT COUNT(*) FROM accounts WHERE NOT EXISTS (SELECT * FROM subscriptions WHERE subscriptions.account_id = accounts.id)

I tried the following python code

accounts = store.find(Account,
    SQL.Not(SQL.Exists(SQL.Select(Subscription.id,
        Subscription.account_id==Account.id)))).count()

but it gets translated to the following SQL:

SELECT COUNT(*) FROM accounts WHERE NOT EXISTS (SELECT subscriptions.id FROM accounts, subscriptions WHERE subscriptions.account_id = accounts.id)

which does not give me the expected result, the accounts table should be removed from the FROM clause in the subquery.

Any suggestion?

I'm using Storm 0.17.0.99, I could upgrade if necessary, but I did not find anything relevant in the changelog.
My database server is PostgreSQL 8.3.11.

Tnx in advance

Edoardo Serra