array join support

clickhouse_sqlalchemy/drivers/base.py

@@ -1,10 +1,10 @@
 import enum
-
 from sqlalchemy import schema, types as sqltypes, exc, util as sa_util
 from sqlalchemy.engine import default, reflection
 from sqlalchemy.sql import (
     compiler, expression, type_api, literal_column, elements
 )
+from sqlalchemy.sql.elements import Label
 from sqlalchemy.types import DATE, DATETIME, FLOAT
 from sqlalchemy.util import warn
 from sqlalchemy.util.compat import inspect_getfullargspec
@@ -195,6 +195,15 @@ def _compose_select_body(
         else:
             text += self.default_from()
 
+        if select._array_join:
+            text += ' \nARRAY JOIN {columns}'.format(
+                columns=', '.join(
+                    col.element.name if isinstance(col, Label) else col.name
+                    for col in select._array_join
+
+                )
+            )
+
         sample_clause = getattr(select, '_sample_clause', None)
 
         if sample_clause is not None:

clickhouse_sqlalchemy/ext/clauses.py

@@ -1,6 +1,10 @@
 from sqlalchemy import util, exc
 from sqlalchemy.sql import type_api
-from sqlalchemy.sql.elements import BindParameter, ColumnElement
+from sqlalchemy.sql.elements import (
+    BindParameter,
+    ColumnElement,
+    ClauseList,
+)
 from sqlalchemy.sql.visitors import Visitable
 
 
@@ -36,3 +40,7 @@ def __init__(self, func):
 
         self.type = type_api.NULLTYPE
         self.func = func
+
+
+class ArrayJoin(ClauseList):
+    __visit_name__ = 'ARRAY_JOIN'

clickhouse_sqlalchemy/orm/query.py

@@ -7,13 +7,15 @@
 class Query(BaseQuery):
     _with_totals = False
     _sample = None
+    _array_join = None
 
     def _compile_context(self, labels=True):
         context = super(Query, self)._compile_context(labels=labels)
         statement = context.statement
 
         statement._with_totals = self._with_totals
         statement._sample_clause = sample_clause(self._sample)
+        statement._array_join = self._array_join
 
         return context
 
@@ -28,6 +30,10 @@ def with_totals(self):
 
         return self
 
+    def array_join(self, *columns):
+        self._array_join = columns
+        return self
+
     def sample(self, sample):
         self._sample = sample
 

clickhouse_sqlalchemy/sql/selectable.py

@@ -9,6 +9,7 @@
 class Select(StandardSelect):
     _with_totals = False
     _sample_clause = None
+    _array_join = None
 
     def with_totals(self):
         self._with_totals = True
@@ -18,5 +19,9 @@ def sample(self, sample):
         self._sample_clause = sample_clause(sample)
         return self
 
+    def array_join(self, *columns):
+        self._array_join = columns
+        return self
+
 
 select = Select

tests/orm/test_select.py

@@ -1,4 +1,10 @@
-from sqlalchemy import Column, exc, func, literal
+from sqlalchemy import (
+    Column,
+    exc,
+    func,
+    literal,
+    literal_column,
+)
 from sqlalchemy import text
 from sqlalchemy import tuple_
 
@@ -9,12 +15,13 @@
 
 
 class SelectTestCase(BaseTestCase):
-    def create_table(self):
+    def create_table(self, *columns):
         metadata = self.metadata()
 
         return Table(
             't1', metadata,
-            Column('x', types.Int32, primary_key=True)
+            Column('x', types.Int32, primary_key=True),
+            *columns
         )
 
     def test_select(self):
@@ -46,6 +53,27 @@ def test_group_by_query(self):
 
         self.assertIn('with_totals', str(ex.exception))
 
+    def make_count_query(self, base_query):
+        return base_query.from_self(func.count(literal_column('*')))
+
+    def test_array_join(self):
+        table = self.create_table(
+            Column('nested.array_column', types.Array(types.Int8)),
+            Column('nested.another_array_column', types.Array(types.Int8))
+        )
+        first_label = table.c['nested.array_column'].label('from_array')
+        second_not_label = table.c['nested.another_array_column']
+        query = session.query(first_label, second_not_label)\
+            .array_join(first_label, second_not_label)
+        self.assertEqual(
+            self.compile(query),
+            'SELECT '
+            '"nested.array_column" AS from_array, '
+            '"nested.another_array_column" AS "t1_nested.another_array_column"'
+            ' FROM t1 '
+            'ARRAY JOIN nested.array_column, nested.another_array_column'
+        )
+
     def test_sample(self):
         table = self.create_table()
 
@@ -54,7 +82,8 @@ def test_sample(self):
             self.compile(query),
             'SELECT x AS t1_x FROM t1 SAMPLE %(param_1)s GROUP BY x'
         )
-
+        q = self.make_count_query(query)
+        self.compile(q)
         self.assertEqual(
             self.compile(query, literal_binds=True),
             'SELECT x AS t1_x FROM t1 SAMPLE 0.1 GROUP BY x'