only filter by the query parameters, not by all fields in the pydanti…

…c model

piccolo_api/crud/endpoints.py

@@ -107,8 +107,9 @@ async def _get_all(self, params: t.Optional[t.Dict] = None):
         """
         query = self.table.select()
         if params:
-            model = self.pydantic_model(**params)
-            for field_name, value in model.dict().items():
+            model_dict = self.pydantic_model(**params).dict()
+            for field_name in params.keys():
+                value = model_dict[field_name]
                 if type(value) == str:
                     query = query.where(
                         getattr(self.table, field_name).ilike(f"%{value}%")