Distinct count implementation for pSQL 🙀

Author: Sibyx

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## 0.7.0 : 2020-08-27
+
+- **Feature**: Now is possible to pass `Distinct` to `Count` to have `COUNT(DISTINCT property)` syntax in pSQL
+- **Tests**: Test for
+
 ## 0.6.1 : 2020-08-04
 
 - **Fix**: Use native `typing.Literal` if possible (Python 3.8 compatibility fix)

docs/functions/count.md

@@ -13,7 +13,7 @@
 | Attribute       | Accepts                                                  | Required |
 |-----------------|----------------------------------------------------------|----------|
 | obj             | `functions.Count`                                        | True     |
-| property        | `properties.Property` `CastOperator`                     | True     |
+| property        | `properties.Property` `CastOperator`  `Distinct`         | True     |
 | alias           | String                                                   | False    |
 
 ## JSON format

duckql/functions/count.py

@@ -9,11 +9,12 @@
 from ..properties import Constant
 from ..properties.property import Property
 from ..structures.cast_operator import CastOperator
+from ..structures.distinct import Distinct
 
 
 class Count(BaseFunction):
     obj: Literal['functions.Count'] = 'functions.Count'
-    property: Union[Property, BaseFunction, Constant, CastOperator]
+    property: Union[Property, BaseFunction, Constant, CastOperator, Distinct]
     alias: str = None
 
     def to_sql(self) -> str:

duckql/functions/tests/test_count.py

@@ -3,6 +3,7 @@
 from duckql.exceptions import ParseError
 from duckql.functions.count import Count
 from duckql.properties.property import Property
+from duckql.structures.distinct import Distinct
 
 
 def test_simple():
@@ -19,3 +20,13 @@ def test_parse_error():
         Count(
             property=Property(name='users.name', alias='name')
         )
+
+
+def test_distinct():
+    my_count = Count(
+        property=Distinct(
+            property=Property(name='users.id')
+        ),
+        alias='distinct_count'
+    )
+    assert str(my_count) == "COUNT(DISTINCT users.id) AS distinct_count"

duckql/properties/tests/test_property.py

@@ -19,6 +19,21 @@ def test_obj(valid_instance: Property):
     assert valid_instance.obj == 'properties.Property'
 
 
+def test_json_field():
+    json_property = Property(
+        name='users.additional_data -> title'
+    )
+    assert str(json_property) == 'users.additional_data -> title'
+
+
+def test_json_field_parser():
+    json_property = Property.parse_raw(
+        '{"obj": "properties.Property", "name": "users.additional_data -> title", "alias": "title"}'
+    )
+    assert json_property.name == 'users.additional_data -> title'
+    assert str(json_property) == 'users.additional_data -> title AS "title"'
+
+
 def test_json_parse(valid_instance: Property):
     assert valid_instance.json() == '{"obj": "properties.Property", "name": "users.name", "alias": "name"}'
 

duckql/version.py

@@ -1 +1 @@
-__version__ = '0.6.1'
+__version__ = '0.7.0'

poetry.lock

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "duckql-python"
-version = "0.6.1"
+version = "0.7.0"
 description = "JSON declarative SQL conversion library"
 authors = ["Jakub Dubec <jakub.dubec@gmail.com>"]
 license = "MIT"