Removes the longest string containing only bytes appearing in
         <parameter>bytesremoved</parameter> from the start of
         <parameter>bytes</parameter>.
        </para>
        <para>
         <literal>ltrim('\x1234567890'::bytea, '\x9012'::bytea)</literal>
         <returnvalue>\x34567890</returnvalue>
        </para></entry>
       </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm>
         <primary>octet_length</primary>
        </indexterm>
        <function>octet_length</function> ( <type>bytea</type> )
        <returnvalue>integer</returnvalue>
       </para>
       <para>
        Returns number of bytes in the binary string.
       </para>
       <para>
        <literal>octet_length('\x123456'::bytea)</literal>
        <returnvalue>3</returnvalue>
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm>
         <primary>overlay</primary>
        </indexterm>
        <function>overlay</function> ( <parameter>bytes</parameter> <type>bytea</type> <literal>PLACING</literal> <parameter>newsubstring</parameter> <type>bytea</type> <literal>FROM</literal> <parameter>start</parameter> <type>integer</type> <optional> <literal>FOR</literal> <parameter>count</parameter> <type>integer</type> </optional> )
        <returnvalue>bytea</returnvalue>
       </para>
       <para>
        Replaces the substring of <parameter>bytes</parameter> that starts at
        the <parameter>start</parameter>'th byte and extends
        for <parameter>count</parameter> bytes
        with <parameter>newsubstring</parameter>.
        If <parameter>count</parameter> is omitted, it defaults to the length
        of <parameter>newsubstring</parameter>.
       </para>
       <para>
        <literal>overlay('\x1234567890'::bytea placing '\002\003'::bytea from 2 for 3)</literal>
        <returnvalue>\x12020390</returnvalue>
       </para></entry>
      </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm>
         <primary>position</primary>
        </indexterm>
        <function>position</function> ( <parameter>substring</parameter> <type>bytea</type> <literal>IN</literal> <parameter>bytes</parameter> <type>bytea</type> )
        <returnvalue>integer</returnvalue>
       </para>
       <para>
        Returns first starting index of the specified
        <parameter>substring</parameter> within
        <parameter>bytes</parameter>, or zero if it's not present.
       </para>
       <para>
        <literal>position('\x5678'::bytea in '\x1234567890'::bytea)</literal>
        <returnvalue>3</returnvalue>
       </para></entry>
      </row>

       <row>
        <entry role="func_table_entry"><para role="func_signature">
         <indexterm>
          <primary>rtrim</primary>
         </indexterm>
         <function>rtrim</function> ( <parameter>bytes</parameter> <type>bytea</type>,
         <parameter>bytesremoved</parameter> <type>bytea</type> )
         <returnvalue>bytea</returnvalue>
        </para>
        <para>
         Removes the longest string containing only bytes appearing in
         <parameter>bytesremoved</parameter> from the end of
         <parameter>bytes</parameter>.
        </para>
        <para>
         <literal>rtrim('\x1234567890'::bytea, '\x9012'::bytea)</literal>
         <returnvalue>\x12345678</returnvalue>
        </para></entry>
       </row>

      <row>
       <entry role="func_table_entry"><para role="func_signature">
        <indexterm>
         <primary>substring</primary>
        </indexterm>
        <function>substring</function> ( <parameter>bytes</parameter> <type>bytea</type> <optional> <literal>FROM</literal> <parameter>start</parameter> <type>integer</type> </optional> <optional> <literal>FOR</literal> <parameter>count</parameter> <type>integer</type> </optional> )
        <returnvalue>bytea</returnvalue>
       </para>