15.29. HQL functions

<div class="paragraph">

Beyond the JPQL standardized functions, HQL makes some additional functions available regardless of the underlying database in use.

</div>
<div class="dlist">
<dl>
<dt class="hdlist1">BIT_LENGTH</dt>
<dd>

Returns the length of binary data.

</dd>
</dl>
</div>
<div class="exampleblock">
<div class="content">
<div class="listingblock">
<div class="content">
<pre class="prettyprint highlight">`List&lt;Number&gt; bits = entityManager.createQuery(
    "select bit_length( c.duration ) " +
    "from Call c ", Number.class )
.getResultList();`</pre>
</div>
</div>
</div>
</div>
<div class="dlist">
<dl>
<dt class="hdlist1">CAST</dt>
<dd>

Performs a SQL cast.
The cast target should name the Hibernate mapping type to use.
See the [data types](#basic-provided) chapter on for more information.

</dd>
</dl>
</div>
<div class="exampleblock">
<div class="content">
<div class="listingblock">
<div class="content">
<pre class="prettyprint highlight">`List&lt;String&gt; durations = entityManager.createQuery(
    "select cast( c.duration as string ) " +
    "from Call c ", String.class )
.getResultList();`</pre>
</div>
</div>
</div>
</div>
<div class="dlist">
<dl>
<dt class="hdlist1">EXTRACT</dt>
<dd>

Performs a SQL extraction on datetime values.
An extraction extracts parts of the datetime (the year, for example).

</dd>
</dl>
</div>
<div class="exampleblock">
<div class="content">
<div class="listingblock">
<div class="content">
<pre class="prettyprint highlight">`List&lt;Integer&gt; years = entityManager.createQuery(
    "select extract( YEAR from c.timestamp ) " +
    "from Call c ", Integer.class )
.getResultList();`</pre>
</div>
</div>
</div>
</div>
<div class="paragraph">

See the abbreviated forms below.

</div>
<div class="dlist">
<dl>
<dt class="hdlist1">YEAR</dt>
<dd>

Abbreviated extract form for extracting the year.

</dd>
</dl>
</div>
<div class="exampleblock">
<div class="content">
<div class="listingblock">
<div class="content">
<pre class="prettyprint highlight">`List&lt;Integer&gt; years = entityManager.createQuery(
    "select year( c.timestamp ) " +
    "from Call c ", Integer.class )
.getResultList();`</pre>
</div>
</div>
</div>
</div>
<div class="dlist">
<dl>
<dt class="hdlist1">MONTH</dt>
<dd>

Abbreviated extract form for extracting the month.

</dd>
<dt class="hdlist1">DAY</dt>
<dd>

Abbreviated extract form for extracting the day.

</dd>
<dt class="hdlist1">HOUR</dt>
<dd>

Abbreviated extract form for extracting the hour.

</dd>
<dt class="hdlist1">MINUTE</dt>
<dd>

Abbreviated extract form for extracting the minute.

</dd>
<dt class="hdlist1">SECOND</dt>
<dd>

Abbreviated extract form for extracting the second.

</dd>
<dt class="hdlist1">STR</dt>
<dd>

Abbreviated form for casting a value as character data.

</dd>
</dl>
</div>
<div class="exampleblock">
<div class="content">
<div class="listingblock">
<div class="content">
<pre class="prettyprint highlight">`List&lt;String&gt; timestamps = entityManager.createQuery(
    "select str( c.timestamp ) " +
    "from Call c ", String.class )
.getResultList();`</pre>
</div>
</div>
</div>
</div>
</div>
<div class="sect2">