diff --git a/lib/dl_connector_clickhouse/dl_connector_clickhouse/formula/definitions/functions_window.py b/lib/dl_connector_clickhouse/dl_connector_clickhouse/formula/definitions/functions_window.py
index 6918da88f..385f1c63f 100644
--- a/lib/dl_connector_clickhouse/dl_connector_clickhouse/formula/definitions/functions_window.py
+++ b/lib/dl_connector_clickhouse/dl_connector_clickhouse/formula/definitions/functions_window.py
@@ -34,7 +34,7 @@ class WinLagClickHouseBase(base.WinLagBase):
             SUPPORTED_DIALECTS,
             translation=lambda x, offset=sa.literal(1), default=sa.null(), *_: (  # noqa: B008
                 base.lag_implementation(
-                    x,
+                    sa.func.toNullable(x),
                     offset=offset,
                     default=default,
                     lag_name="lagInFrame",