Support for SAMPLE BY in schemas

Author: asantoni

clickhouse_backend/backend/schema.py

@@ -254,13 +254,16 @@ def _model_extra_sql(self, model, engine):
             order_by = engine.order_by
             partition_by = engine.partition_by
             primary_key = engine.primary_key
+            sample_by = engine.sample_by
 
             if order_by is not None:
                 yield "ORDER BY (%s)" % self._get_expression(model, *order_by)
             if partition_by:
                 yield "PARTITION BY (%s)" % self._get_expression(model, *partition_by)
             if primary_key is not None:
                 yield "PRIMARY KEY (%s)" % self._get_expression(model, *primary_key)
+            if sample_by is not None:
+                yield "SAMPLE BY (%s)" % self._get_expression(model, *sample_by)
         if engine.settings:
             result = []
             for setting, value in engine.settings.items():

clickhouse_backend/models/engines.py

@@ -128,6 +128,7 @@ def __init__(
         order_by=None,
         partition_by=None,
         primary_key=None,
+        sample_by=None,
         **settings,
     ):
         assert (
@@ -136,8 +137,9 @@ def __init__(
         self.order_by = order_by
         self.primary_key = primary_key
         self.partition_by = partition_by
+        self.sample_by = sample_by
 
-        for key in ["order_by", "primary_key", "partition_by"]:
+        for key in ["order_by", "primary_key", "partition_by", "sample_by"]:
             value = getattr(self, key)
             if value is not None:
                 if isinstance(value, str) or not isinstance(value, Iterable):