diff --git a/ibis/backends/oracle/__init__.py b/ibis/backends/oracle/__init__.py
index 519404c08452..d2b05cc54eb4 100644
--- a/ibis/backends/oracle/__init__.py
+++ b/ibis/backends/oracle/__init__.py
@@ -243,7 +243,7 @@ def _metadata(self, query: str) -> Iterable[tuple[str, dt.DataType]]:
             t.c.data_type,
             t.c.data_precision,
             t.c.data_scale,
-            case([(t.c.nullable == "Y", True)], else_=False).label("nullable"),
+            case((t.c.nullable == "Y", True), else_=False).label("nullable"),
         ).where(t.c.table_name == name)
 
         with self.begin() as con: