diff --git a/utils/funcexp/func_dayname.cpp b/utils/funcexp/func_dayname.cpp
index 3825bc1a3..325fb2f4a 100644
--- a/utils/funcexp/func_dayname.cpp
+++ b/utils/funcexp/func_dayname.cpp
@@ -145,7 +145,9 @@ string Func_dayname::getStrVal(rowgroup::Row& row,
                                bool& isNull,
                                CalpontSystemCatalog::ColType& op_ct)
 {
-    uint32_t weekday = getIntVal(row, parm, isNull, op_ct);
+    int32_t weekday = getIntVal(row, parm, isNull, op_ct);
+    if (weekday == -1)
+        return "";
     return helpers::weekdayFullNames[weekday];
 }
 
diff --git a/utils/funcexp/func_monthname.cpp b/utils/funcexp/func_monthname.cpp
index dbe5aa513..8d8200775 100644
--- a/utils/funcexp/func_monthname.cpp
+++ b/utils/funcexp/func_monthname.cpp
@@ -47,7 +47,9 @@ string Func_monthname::getStrVal(rowgroup::Row& row,
                                  bool& isNull,
                                  CalpontSystemCatalog::ColType& op_ct)
 {
-    uint32_t month = getIntVal(row, parm, isNull, op_ct);
+    int32_t month = getIntVal(row, parm, isNull, op_ct);
+    if (month == -1)
+        return "";
     return helpers::monthFullNames[month];
 }