diff --git a/test/unit/rx-collection.test.ts b/test/unit/rx-collection.test.ts
index ab7d581e842..40396dd0d9b 100644
--- a/test/unit/rx-collection.test.ts
+++ b/test/unit/rx-collection.test.ts
@@ -1261,6 +1261,79 @@ describe('rx-collection.test.ts', () => {
                     c.database.destroy();
                 });
             });
+            /**
+             * @link https://github.com/pubkey/rxdb/pull/4775
+             */
+            it('#4775 count() broken on primary key', async () => {
+                // create a schema
+                const mySchema = {
+                    version: 0,
+                    primaryKey: 'passportId',
+                    type: 'object',
+                    properties: {
+                        passportId: {
+                            type: 'string',
+                            maxLength: 100
+                        },
+                        firstName: {
+                            type: 'string'
+                        },
+                        lastName: {
+                            type: 'string'
+                        },
+                        age: {
+                            type: 'integer',
+                            minimum: 0,
+                            maximum: 150
+                        }
+                    }
+                };
+
+                const name = randomCouchString(10);
+                const db = await createRxDatabase({
+                    name,
+                    storage: config.storage.getStorage(),
+                    eventReduce: true,
+                    ignoreDuplicate: true
+                });
+                const collections = await db.addCollections({
+                    mycollection: {
+                        schema: mySchema
+                    }
+                });
+
+                // insert a document
+                await collections.mycollection.insert({
+                    passportId: 'foobar2',
+                    firstName: 'Bob',
+                    lastName: 'Kelso',
+                    age: 56
+                });
+                await collections.mycollection.insert({
+                    passportId: 'foobar3',
+                    firstName: 'Bob',
+                    lastName: 'Kelso',
+                    age: 56
+                });
+
+                const countResult = await collections.mycollection
+                    .count({
+                        selector: {
+                            passportId: {
+                                $eq: 'foobar'
+                            }
+                        }
+                    }).exec();
+
+                /*
+                 * assert things,
+                 * here your tests should fail to show that there is a bug
+                 */
+                assert.strictEqual(countResult, 0);
+
+                // clean up afterwards
+                db.destroy();
+            });
         });
         config.parallel('.bulkUpsert()', () => {
             it('insert and update', async () => {
diff --git a/test/unit/rx-storage-query-correctness.test.ts b/test/unit/rx-storage-query-correctness.test.ts
index 7a80c491bb8..cd1a3c9efcb 100644
--- a/test/unit/rx-storage-query-correctness.test.ts
+++ b/test/unit/rx-storage-query-correctness.test.ts
@@ -705,6 +705,14 @@ config.parallel('rx-storage-query-correctness.test.ts', () => {
     testCorrectQueries({
         testTitle: '$eq operator',
         data: [
+            {
+                id: 'zero',
+                nonPrimaryString: 'zero',
+                integer: 0,
+                number: 0,
+                boolean: false,
+                null: 'not-null'
+            },
             {
                 id: 'one',
                 nonPrimaryString: 'one',
@@ -712,6 +720,14 @@ config.parallel('rx-storage-query-correctness.test.ts', () => {
                 number: 1,
                 boolean: true,
                 null: null
+            },
+            {
+                id: 'two',
+                nonPrimaryString: 'two',
+                integer: 2,
+                number: 2,
+                boolean: false,
+                null: 'not-null'
             }
         ],
         schema: {