title: remove non-numeric characters in a column (character varying), postgresql (9.3.5)
body: <p>I need to remove non-numeric characters in a column (character varying) and keep numeric values in postgresql 9.3.5.</p>
  
  <p>Examples:</p>
  
  <pre><code>1) "ggg" =&gt; ""
  2) "3,0 kg" =&gt; "3,0"
  3) "15 kg." =&gt; "15"
  4) ...
  </code></pre>
  
  <p>There are a few problems, some values are like:</p>
  
  <pre><code>1) "2x3,25" 
  2) "96+109" 
  3) ...
  </code></pre>
  
  <p>These need to remain as is (i.e when containing non-numeric characters between numeric characters - do nothing).</p>