diff --git a/4-auth/books/model-datastore.js b/4-auth/books/model-datastore.js
index f53b1293cd..b3dc851baf 100644
--- a/4-auth/books/model-datastore.js
+++ b/4-auth/books/model-datastore.js
@@ -105,7 +105,7 @@ function list (limit, token, cb) {
 // [START listby]
 function listBy (userId, limit, token, cb) {
   var q = ds.createQuery([kind])
-    .filter('createdById =', userId)
+    .filter('createdById', '=', userId)
     .limit(limit)
     .start(token);
 
diff --git a/5-logging/books/model-datastore.js b/5-logging/books/model-datastore.js
index 6acac77093..10b9834881 100644
--- a/5-logging/books/model-datastore.js
+++ b/5-logging/books/model-datastore.js
@@ -104,7 +104,7 @@ function list (limit, token, cb) {
 // user.
 function listBy (userId, limit, token, cb) {
   var q = ds.createQuery([kind])
-    .filter('createdById =', userId)
+    .filter('createdById', '=', userId)
     .limit(limit)
     .start(token);
 
diff --git a/6-pubsub/books/model-datastore.js b/6-pubsub/books/model-datastore.js
index f2d1c86484..b28af3a0e9 100644
--- a/6-pubsub/books/model-datastore.js
+++ b/6-pubsub/books/model-datastore.js
@@ -105,7 +105,7 @@ function list (limit, token, cb) {
 // user.
 function listBy (userId, limit, token, cb) {
   var q = ds.createQuery([kind])
-    .filter('createdById =', userId)
+    .filter('createdById', '=', userId)
     .limit(limit)
     .start(token);
 
diff --git a/7-gce/books/model-datastore.js b/7-gce/books/model-datastore.js
index 4c29100c95..197510b996 100644
--- a/7-gce/books/model-datastore.js
+++ b/7-gce/books/model-datastore.js
@@ -105,7 +105,7 @@ function list (limit, token, cb) {
 // user.
 function listBy (userId, limit, token, cb) {
   var q = ds.createQuery([kind])
-    .filter('createdById =', userId)
+    .filter('createdById', '=', userId)
     .limit(limit)
     .start(token);
 
diff --git a/optional-container-engine/books/model-datastore.js b/optional-container-engine/books/model-datastore.js
index 4c29100c95..197510b996 100644
--- a/optional-container-engine/books/model-datastore.js
+++ b/optional-container-engine/books/model-datastore.js
@@ -105,7 +105,7 @@ function list (limit, token, cb) {
 // user.
 function listBy (userId, limit, token, cb) {
   var q = ds.createQuery([kind])
-    .filter('createdById =', userId)
+    .filter('createdById', '=', userId)
     .limit(limit)
     .start(token);