diff --git a/querydsl/src/main/java/org/baeldung/dao/PersonDao.java b/querydsl/src/main/java/org/baeldung/dao/PersonDao.java
index cc193de44b..17be05bff8 100644
--- a/querydsl/src/main/java/org/baeldung/dao/PersonDao.java
+++ b/querydsl/src/main/java/org/baeldung/dao/PersonDao.java
@@ -2,11 +2,22 @@ package org.baeldung.dao;
 
 import org.baeldung.entity.Person;
 
+import javax.persistence.Tuple;
 import java.util.List;
+import java.util.Map;
 
 public interface PersonDao {
 
     public Person save(Person person);
 
     public List<Person> findPersonsByFirstnameQueryDSL(String firstname);
+
+    public List<Person> findPersonsByFirstnameAndSurnameQueryDSL(String firstname, String surname);
+
+    public List<Person> findPersonsByFirstnameInDescendingOrderQueryDSL(String firstname);
+
+    public int findMaxAge();
+
+    public Map<String, Integer> findMaxAgeByName();
+
 }
\ No newline at end of file