CREATE COLLATION num_ignore_punct (provider = icu, deterministic = false, locale = 'und-u-ka-shifted-kn');
SELECT 'id-45' < 'id-123' COLLATE num_ignore_punct; -- true
SELECT 'w;x*y-z' = 'wxyz' COLLATE num_ignore_punct; -- true
</programlisting>

    Many of the available options are described in <xref
    linkend="icu-collation-settings"/>, or see <xref
    linkend="icu-external-references"/> for more details.
   </para>

   <sect3 id="icu-collation-comparison-levels">
    <title>ICU Comparison Levels</title>

    <para>
     Comparison of two strings (collation) in ICU is determined by a
     multi-level process, where textual features are grouped into
     "levels". Treatment of each level is controlled by the <link
     linkend="icu-collation-settings-table">collation settings</link>. Higher
     levels correspond to finer textual features.
    </para>

    <para>
     <xref linkend="icu-collation-levels"/> shows which textual feature
     differences are considered significant when determining equality at the
     given level. The Unicode character <literal>U+2063</literal> is an
     invisible separator, and as seen in the table, is ignored for at all
     levels of comparison less than <literal>identic</literal>.
    </para>

     <table id="icu-collation-levels">
      <title>ICU Collation Levels</title>
      <tgroup cols="8">
       <colspec colname="col1" colwidth="1*"/>
       <colspec colname="col2" colwidth="1.25*"/>
       <colspec colname="col3" colwidth="1*"/>
       <colspec colname="col4" colwidth="1*"/>
       <colspec colname="col5" colwidth="1*"/>
       <colspec colname="col6" colwidth="1*"/>
       <colspec colname="col7" colwidth="1*"/>
       <colspec colname="col8" colwidth="1*"/>

       <thead>
        <row>
         <entry>Level</entry>
         <entry>Description</entry>
         <entry><literal>'f' = 'f'</literal></entry>
         <entry><literal>'ab' = U&amp;'a\2063b'</literal></entry>
         <entry><literal>'x-y' = 'x_y'</literal></entry>
         <entry><literal>'g' = 'G'</literal></entry>
         <entry><literal>'n' = 'ñ'</literal></entry>
         <entry><literal>'y' = 'z'</literal></entry>
        </row>
       </thead>

       <tbody>
        <row>
         <entry>level1</entry>
         <entry>Base Character</entry>
         <entry><literal>true</literal></entry>
         <entry><literal>true</literal></entry>
         <entry><literal>true</literal></entry>
         <entry><literal>true</literal></entry>
         <entry><literal>true</literal></entry>
         <entry><literal>false</literal></entry>
        </row>
        <row>
         <entry>level2</entry>
         <entry>Accents</entry>
         <entry><literal>true</literal></entry>
         <entry><literal>true</literal></entry>
         <entry><literal>true</literal></entry>
         <entry><literal>true</literal></entry>
         <entry><literal>false</literal></entry>
         <entry><literal>false</literal></entry>
        </row>
        <row>
         <entry>level3</entry>
         <entry>Case/Variants</entry>
         <entry><literal>true</literal></entry>
         <entry><literal>true</literal></entry>
         <entry><literal>true</literal></entry>
         <entry><literal>false</literal></entry>
         <entry><literal>false</literal></entry>
         <entry><literal>false</literal></entry>
        </row>
        <row>
         <entry>level4</entry>
         <entry>Punctuation<footnote><para>only with
         <literal>ka-shifted</literal>; see <xref
         linkend="icu-collation-settings-table"/></para></footnote></entry>
         <entry><literal>true</literal></entry>
         <entry><literal>true</literal></entry>
         <entry><literal>false</literal></entry>
         <entry><literal>false</literal></entry>
         <entry><literal>false</literal></entry>
         <entry><literal>false</literal></entry>
        </row>
        <row>
         <entry>identic</entry>
         <entry>All</entry>
         <entry><literal>true</literal></entry>