16.3. Selecting an expression

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The simplest form of selecting an expression is selecting a particular attribute from an entity.
But this expression might also represent an aggregation, a mathematical operation, etc.

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<div class="title">Example 410. Selecting an attribute</div>
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<pre class="prettyprint highlight">`CriteriaBuilder builder = entityManager.getCriteriaBuilder();

CriteriaQuery&lt;String&gt; criteria = builder.createQuery( String.class );
Root&lt;Person&gt; root = criteria.from( Person.class );
criteria.select( root.get( Person_.nickName ) );
criteria.where( builder.equal( root.get( Person_.name ), "John Doe" ) );

List&lt;String&gt; nickNames = entityManager.createQuery( criteria ).getResultList();`</pre>
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In this example, the query is typed as `java.lang.String` because that is the anticipated type of the results (the type of the `Person#nickName` attribute is `java.lang.String`).
Because a query might contain multiple references to the `Person` entity, attribute references always need to be qualified.
This is accomplished by the `Root#get` method call.

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