wip improved types

Author: ym-pett

narwhals/_sql/typing.py

@@ -7,6 +7,7 @@
 if TYPE_CHECKING:
     from narwhals._sql.dataframe import SQLLazyFrame
     from narwhals._sql.expr import SQLExpr
+    from narwhals.dtypes import Boolean
 
     SQLExprAny = SQLExpr[Any, Any]
     SQLLazyFrameAny = SQLLazyFrame[Any, Any, Any]
@@ -17,6 +18,23 @@
 
 
 class NativeSQLExpr(NativeExpr):
-    def __gt__(self, other: Any) -> Any: ...
+    # TODO @mp: fix input type for all these!
+    def __gt__(self, value: float) -> Boolean: ...
 
-    def __le__(self, other: Any) -> Any: ...
+    def __lt__(self, value: float) -> Boolean: ...
+
+    def __ge__(self, value: float) -> Boolean: ...
+
+    def __le__(self, value: float) -> Boolean: ...
+
+    def __eq__(self, value: float) -> Boolean: ...
+
+    def __ne__(self, value: float) -> Boolean: ...
+    # do we want any more of the arithmetic methods? I wasn't sure between lefthan & righthand methods..
+    def __sub__(self, value: float) -> Any: ...
+
+    def __add__(self, value: float) -> Any: ...
+
+    def __truediv__(self, value: float) -> Any: ...
+
+    def __mul__(self, value: float) -> Any: ...