diff --git a/extensions/functions_datetime.yaml b/extensions/functions_datetime.yaml
index 5847c276c..d82c71247 100644
--- a/extensions/functions_datetime.yaml
+++ b/extensions/functions_datetime.yaml
@@ -374,6 +374,9 @@ scalar_functions:
             value: interval_year
           - name: y
             value: interval_year
+        options:
+          days_in_year:
+            values: [ YEAR_366DAYS, YEAR_365DAYS, YEAR_360DAYS ]
         return: interval_year
   -
     name: "subtract"