diff --git a/jsonsubschema/_checkers.py b/jsonsubschema/_checkers.py
index d2033a1..f25a7e4 100644
--- a/jsonsubschema/_checkers.py
+++ b/jsonsubschema/_checkers.py
@@ -359,10 +359,6 @@ def _joinString(s1, s2):
                 if s1_new_pattern and s2_new_pattern:
                     ret["pattern"] = "^" + s1_new_pattern + \
                         "$|^" + s2_new_pattern + "$"
-                elif s1_new_pattern:
-                    ret["pattern"] = "^" + s1_new_pattern + "$"
-                elif s2_new_pattern:
-                    ret["pattern"] = "^" + s2_new_pattern + "$"
                 return JSONTypeString(ret)
             else:
                 return JSONanyOf({"anyOf": [s1, s2]})
diff --git a/test/test_string.py b/test/test_string.py
index b5e1337..ae6b285 100644
--- a/test/test_string.py
+++ b/test/test_string.py
@@ -212,6 +212,11 @@ def test_enum3(self):
         with self.subTest():
             self.assertFalse(isSubschema(s2, s1))
 
+    def test_enum4(self):
+        s1 = {"anyOf": [{"enum": ["a", "b", "c"]}, {"type": "string"}]}
+        s2 = {"type": "string"}
+        self.assertTrue(isEquivalent(s1, s2))
+
     def test_not_enum1(self):
         s1 = {"type": "string", "not": {"enum": ["a"]}}
         s2 = {"type": "string"}