title: display non-printable ascii characters in SQL as :ascii: or :print: does not work
body: <p>I am trying to fetch all non-printable ASCII characters from DESCRIPTION field in a table using SQL in TOAD however the below query is not working . </p>
  
  <pre><code>select 
  regexp_instr(a.description,'[^[:ascii:]]') as description from
  poline a where a.ponum='XXX' and a.siteid='YYY' and 
  regexp_instr(a.description,'[^[:ascii:]]') &gt; 0 
  </code></pre>
  
  <p>the above query bought error ORA-127729: invalid character class in regular expression. I tried :print: instead of :ascii: however it didn't bring any result. Below is the description for this record which has non-printable characters. </p>
  
  <pre><code>Sherlock 16 x 6.5” Wide Wheelbarrow wheel .M100P.10R – Effluent care bacteria and enzyme formulation
  </code></pre>