title: Remove prefix and suffix with oracle regex
body: <p>I have some records with that come with a prefix and suffix (may or may not come).
  I'm trying to figure the <code>REGEXP_REPLACE</code> that will always return me a parametrized value.</p>
  
  <p>My attempt so far is:</p>
  
  <pre><code>with teste as (
  select '+123145@domain.com' as num from dual
  union
  select '0054321@domain.com' as num from dual
  union
  select '006789' as num from dual
  union
  select '+9876' as num from dual
  union
  select '13579@domain.com' as num from dual
  union
  select '123456789' as num from dual
  )
  select REGEXP_REPLACE(num,'^00(.*)\@.*$|^\+(.*)\@.*$','\1') from teste
  </code></pre>
  
  <p>but is not quite there.</p>
  
  <p>The output of that should be:</p>
  
  <pre><code>num
  12345
  54321
  6789
  9876
  13579
  123456789
  </code></pre>