title: Querydsl - How to join multiple column's value in select expression?
body: <p>I'm using Querydsl with spring data jpa. I've implemented custom repository to find out person names. The person entity looks like as follows:</p>
  
  <pre><code>@Entity
  @Table(name = "persons")
  public class Person {
      @Id
      @GeneratedValue(strategy = GenerationType.IDENTITY)
      @Column(name = "id", nullable = false, updatable = false)
      private Long id;
  
      @Column(name = "initial")
      private String initial;
  
      @Column(name = "first_name")
      private String firstName;
  
      @Column(name = "last_name")
      private String lastName;
  
      @Column(name = "archived")
      private Boolean archived;
  
      //Other columns here.. &amp;&amp; Getter setter goes here
  }
  </code></pre>
  
  <p>The implemented custom repository:</p>
  
  <pre><code>@Repository
  public class PersonRepositoryImpl extends QueryDslRepositorySupport 
          implements PersonRepositoryCustom {
      public PersonRepositoryImpl() {
          super(Person.class);
      }
  
      @Override
      public List&lt;String&gt; getPersonNames() {
          return getQuerydsl()
                  .createQuery()
                  .from(QPerson.person)
                  .where(QPerson.person.archived.eq(Boolean.FALSE))
                  .select(/* 
                      want to select as a full name like
                      initial + firstName + lastName
                    */)
                  .fetch();
      }
  }
  </code></pre>
  
  <p>In the select expression, I would like to join three columns to construct full name. If database has a record like the following -</p>
  
  <pre><code>id | initial | firstName | lastName | archived | ...
  ----------------------------------------------------
  1  | "Mr"    | "John"    | "Snow"   | 0        | ...
  </code></pre>
  
  <p>then I would like to select as "Mr John Snow". <strong>Is there any way to do that?</strong> </p>
  
  <p>I don't want to select whole record to concat the value because entity has others column and lots of associations and it's not good to load whole record.</p>