done

lib/python3.11/site-packages/narwhals/_sql/group_by.py

@@ -0,0 +1,45 @@
+from __future__ import annotations
+
+from typing import TYPE_CHECKING, Protocol
+
+from narwhals._compliant.group_by import CompliantGroupBy, ParseKeysGroupBy
+from narwhals._compliant.typing import CompliantLazyFrameT, NativeExprT_co
+from narwhals._sql.typing import SQLExprT_contra
+from narwhals._utils import zip_strict
+
+if TYPE_CHECKING:
+    from collections.abc import Iterable, Iterator
+
+
+class SQLGroupBy(
+    ParseKeysGroupBy[CompliantLazyFrameT, SQLExprT_contra],
+    CompliantGroupBy[CompliantLazyFrameT, SQLExprT_contra],
+    Protocol[CompliantLazyFrameT, SQLExprT_contra, NativeExprT_co],
+):
+    _keys: list[str]
+    _output_key_names: list[str]
+
+    def _evaluate_expr(self, expr: SQLExprT_contra, /) -> Iterator[NativeExprT_co]:
+        output_names = expr._evaluate_output_names(self.compliant)
+        aliases = (
+            expr._alias_output_names(output_names)
+            if expr._alias_output_names
+            else output_names
+        )
+        native_exprs = expr(self.compliant)
+        if expr._is_multi_output_unnamed():
+            exclude = {*self._keys, *self._output_key_names}
+            for native_expr, name, alias in zip_strict(
+                native_exprs, output_names, aliases
+            ):
+                if name not in exclude:
+                    yield expr._alias_native(native_expr, alias)
+        else:
+            for native_expr, alias in zip_strict(native_exprs, aliases):
+                yield expr._alias_native(native_expr, alias)
+
+    def _evaluate_exprs(
+        self, exprs: Iterable[SQLExprT_contra], /
+    ) -> Iterator[NativeExprT_co]:
+        for expr in exprs:
+            yield from self._evaluate_expr(expr)