15.16.1. Using DISTINCT with SQL projections

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For SQL projections, `DISTINCT` needs to be passed to the database because the duplicated entries need to be filtered out before being returned to the database client.

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<div class="title">Example 376. Using DISTINCT with projection queries example</div>
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<pre class="prettyprint highlight">`List&lt;String&gt; lastNames = entityManager.createQuery(
    "select distinct p.lastName " +
    "from Person p", String.class)
.getResultList();`</pre>
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When running the query above, Hibernate generates the following SQL query:

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<pre class="prettyprint highlight">`SELECT DISTINCT
    p.last_name as col_0_0_
FROM person p`</pre>
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For this particular use case, passing the `DISTINCT` keyword from JPQL/HQL to the database is the right thing to do.

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