<returnvalue>ltree</returnvalue>
       </para>
       <para>
        Returns first array entry that matches <type>lquery</type>,
        or <literal>NULL</literal> if none.
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <type>ltree[]</type> <literal>?@</literal> <type>ltxtquery</type>
        <returnvalue>ltree</returnvalue>
       </para>
       <para>
        Returns first array entry that matches <type>ltxtquery</type>,
        or <literal>NULL</literal> if none.
       </para></entry>
      </row>
     </tbody>
    </tgroup>
  </table>

  <para>
   The operators <literal>&lt;@</literal>, <literal>@&gt;</literal>,
   <literal>@</literal> and <literal>~</literal> have analogues
   <literal>^&lt;@</literal>, <literal>^@&gt;</literal>, <literal>^@</literal>,
   <literal>^~</literal>, which are the same except they do not use
   indexes.  These are useful only for testing purposes.
  </para>

  <para>
   The available functions are shown in <xref linkend="ltree-func-table"/>.
  </para>

  <table id="ltree-func-table">
   <title><type>ltree</type> Functions</title>
    <tgroup cols="1">
     <thead>
      <row>
       <entry role="func_table_entry"><para role="func_signature">
        Function
       </para>
       <para>
        Description
       </para>
       <para>
        Example(s)
       </para></entry>
      </row>
     </thead>

     <tbody>
      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm><primary>subltree</primary></indexterm>
        <function>subltree</function> ( <type>ltree</type>, <parameter>start</parameter> <type>integer</type>, <parameter>end</parameter> <type>integer</type> )
        <returnvalue>ltree</returnvalue>
       </para>
       <para>
        Returns subpath of <type>ltree</type> from
        position <parameter>start</parameter> to
        position <parameter>end</parameter>-1 (counting from 0).
       </para>
       <para>
        <literal>subltree('Top.Child1.Child2', 1, 2)</literal>
        <returnvalue>Child1</returnvalue>
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm><primary>subpath</primary></indexterm>
        <function>subpath</function> ( <type>ltree</type>, <parameter>offset</parameter> <type>integer</type>, <parameter>len</parameter> <type>integer</type> )
        <returnvalue>ltree</returnvalue>
       </para>
       <para>
        Returns subpath of <type>ltree</type> starting at
        position <parameter>offset</parameter>, with
        length <parameter>len</parameter>.  If <parameter>offset</parameter>
        is negative, subpath starts that far from the end of the path.
        If <parameter>len</parameter> is negative, leaves that many labels off
        the end of the path.
       </para>
       <para>
        <literal>subpath('Top.Child1.Child2', 0, 2)</literal>
        <returnvalue>Top.Child1</returnvalue>
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <function>subpath</function> ( <type>ltree</type>, <parameter>offset</parameter> <type>integer</type> )
        <returnvalue>ltree</returnvalue>
       </para>
       <para>
        Returns subpath of <type>ltree</type> starting at
        position <parameter>offset</parameter>, extending to end of path.
        If <parameter>offset</parameter> is negative, subpath starts that far
        from the end of the path.
       </para>
       <para>
        <literal>subpath('Top.Child1.Child2', 1)</literal>
        <returnvalue>Child1.Child2</returnvalue>
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm><primary>nlevel</primary></indexterm>
        <function>nlevel</function> ( <type>ltree</type> )
        <returnvalue>integer</returnvalue>
       </para>