diff --git a/mongodb/src/main/java/org/apache/calcite/adapter/mongodb/MongoRules.java b/mongodb/src/main/java/org/apache/calcite/adapter/mongodb/MongoRules.java
index fa10035746c2..00c14f1c683b 100644
--- a/mongodb/src/main/java/org/apache/calcite/adapter/mongodb/MongoRules.java
+++ b/mongodb/src/main/java/org/apache/calcite/adapter/mongodb/MongoRules.java
@@ -114,10 +114,14 @@ static String quote(String s) {
   }
 
   private static boolean needsQuote(String s) {
-    for (int i = 0, n = s.length(); i < n; i++) {
+    if (!s.isEmpty()
+        && (!Character.isJavaIdentifierStart(s.charAt(0)) || s.charAt(0) == '$')) {
+      return true;
+    }
+
+    for (int i = 1, n = s.length(); i < n; i++) {
       char c = s.charAt(i);
-      if (!Character.isJavaIdentifierPart(c)
-          || c == '$') {
+      if (!Character.isJavaIdentifierPart(c)) {
         return true;
       }
     }
diff --git a/mongodb/src/test/java/org/apache/calcite/adapter/mongodb/MongoAdapterTest.java b/mongodb/src/test/java/org/apache/calcite/adapter/mongodb/MongoAdapterTest.java
index 61cf6672b53e..f65a5a96eefe 100644
--- a/mongodb/src/test/java/org/apache/calcite/adapter/mongodb/MongoAdapterTest.java
+++ b/mongodb/src/test/java/org/apache/calcite/adapter/mongodb/MongoAdapterTest.java
@@ -109,6 +109,7 @@ public static void setUp() throws Exception {
     doc.put("value", new BsonInt32(1231));
     doc.put("ownerId", new BsonString("531e7789e4b0853ddb861313"));
     doc.put("arr", new BsonArray(Arrays.asList(new BsonString("a"), new BsonString("b"))));
+    doc.put("1_minute_aggregation", new BsonInt32(10));
     datatypes.insertOne(doc);
 
     schema = new MongoSchema(database);
@@ -605,18 +606,22 @@ private CalciteAssert.AssertThat assertModel(URL url) {
                 "{$limit: 5}"));
   }
 
-  @Disabled("broken; [CALCITE-2115] is logged to fix it")
   @Test void testProject() {
     assertModel(MODEL)
         .query("select state, city, 0 as zero from zips order by state, city")
         .limit(2)
-        .returns("STATE=AK; CITY=AKHIOK; ZERO=0\n"
-            + "STATE=AK; CITY=AKIACHAK; ZERO=0\n")
+        .returns("STATE=AK; CITY=ANCHORAGE; ZERO=0\n"
+            + "STATE=AK; CITY=FAIRBANKS; ZERO=0\n")
         .queryContains(
             mongoChecker(
-                "{$project: {CITY: '$city', STATE: '$state'}}",
-                "{$sort: {STATE: 1, CITY: 1}}",
-                "{$project: {STATE: 1, CITY: 1, ZERO: {$literal: 0}}}"));
+                "{$project: {STATE: '$state', CITY: '$city', ZERO: {$literal: 0}}}",
+                "{$sort: {STATE: 1, CITY: 1}}"));
+
+    assertModel(MODEL)
+        .query("select cast(_MAP['1_minute_aggregation'] as INT) as \"1_minute_aggregation\" "
+            + "from \"mongo_raw\".\"datatypes\"")
+        .queryContains(
+            mongoChecker("{$project: {'1_minute_aggregation': 1}}"));
   }
 
   @Test void testFilter() {