add test coverage for count(), group_by(), having() in conjunction with select_from()

[Mike Bayer]

No description provided.

[Former user]

Could this be related to the fact that

len(Item.query().from_statement(compound).all())

returns correct number and

Item.query().from_statement(compound).count()

ignores the compound part and simply counts all Items?

If not, maybe you could give me a clue what could be wrong (because the first statement seems logical to me)?

[Mike Bayer]

yes, count() has fallen out of maintenance and does not interact well with some of the newer options.

your best bet for now is:

select([func.count(1)](func.count(1))).select_from(compound).execute().scalar()

[Mike Bayer]

0.5's Query works fairly well with select_from() and count(), might need more test coverage for group_by() but this should be generally working now.

[Mike Bayer]

[classic@photon2 sqlalchemy]$ git diff
diff --git a/lib/sqlalchemy/orm/query.py b/lib/sqlalchemy/orm/query.py
index 2fae362..a9926b7 100644
--- a/lib/sqlalchemy/orm/query.py
+++ b/lib/sqlalchemy/orm/query.py
@@ -1601,6 +1601,8 @@ class Query(object):
            in the same way as ORDER BY.

         """
+        if self._from_obj:
+            raise Exception("group by coverered")

         if len(criterion) == 1:
             if criterion[0] is None:
@@ -1632,6 +1634,8 @@ class Query(object):
                         having(func.count(Address.id) > 2)

         """
+        if self._from_obj:
+            raise Exception("having coverered")

         criterion = expression._expression_literal_as_text(criterion)

@@ -3061,6 +3065,8 @@ class Query(object):
             session.query(func.count(distinct(User.name)))

         """
+        if self._from_obj:
+            raise Exception("count coverered")
         col = sql.func.count(sql.literal_column('*'))
         return self.from_self(col).scalar()

#!

_
Traceback (most recent call last):
  File "/home/classic/dev/sqlalchemy/test/orm/test_query.py", line 2792, in test_having
    assert [User(name='ed', id=8)] == \
  File "<string>", line 2, in having
  File "/home/classic/dev/sqlalchemy/test/../lib/sqlalchemy/orm/base.py", line 201, in generate
    fn(self, *args[1:], **kw)
  File "/home/classic/dev/sqlalchemy/test/../lib/sqlalchemy/orm/query.py", line 1638, in having
    raise Exception("having coverered")
Exception: having coverered
_______________________________________________________ CountTest.test_multiple_entity _______________________________________________________
Traceback (most recent call last):
  File "/home/classic/dev/sqlalchemy/test/orm/test_query.py", line 2882, in test_multiple_entity
    eq_(q.count(), 5)
  File "/home/classic/dev/sqlalchemy/test/../lib/sqlalchemy/orm/query.py", line 3069, in count
    raise Exception("count coverered")
Exception: count coverered
___________________________________________________________ CountTest.test_nested ____________________________________________________________
Traceback (most recent call last):
  File "/home/classic/dev/sqlalchemy/test/orm/test_query.py", line 2895, in test_nested
    eq_(q.count(), 5)
  File "/home/classic/dev/sqlalchemy/test/../lib/sqlalchemy/orm/query.py", line 3069, in count
    raise Exception("count coverered")
Exception: count coverered
___________________________________________________________ ExpressionTest.test_in ___________________________________________________________
Traceback (most recent call last):
  File "/home/classic/dev/sqlalchemy/test/orm/test_query.py", line 1564, in test_in
    s = session.query(User.id).join(User.addresses).group_by(User.id).\
  File "<string>", line 2, in group_by
  File "/home/classic/dev/sqlalchemy/test/../lib/sqlalchemy/orm/base.py", line 201, in generate
    fn(self, *args[1:], **kw)
  File "/home/classic/dev/sqlalchemy/test/../lib/sqlalchemy/orm/query.py", line 1605, in group_by
    raise Exception("group by coverered")
Exception: group by coverered
==================================================== 4 failed, 245 passed in 3.66 seconds ====================================================

[Mike Bayer]

that's just test_query there are more elsewhere