title: How can I fetch only the unique values of column 2 based on column 1 values?
body: <pre><code>admin_id  |  country_id
  -------------------------
     5            44
     5            32
     3            2
     92           32
     92           30
     5            30
  </code></pre>
  <p>I want to fetch all <code>country_id</code> values if <code>admin_id</code> <code>$_Session['admin']['id'] = 5</code> AND all the <code>country_id</code> values if <code>admin_id = 92</code>.</p>
  <p>There can be duplicates because many admins can have the same <code>country_id</code>, so in that case I want to keep ONLY the <code>country_id</code> of the <code>admin_id=92 </code></p>
  <p>The desired output:</p>
  <pre><code>admin_id  |  country_id
  -------------------------
     5            44             
     92           32
     92           30
  </code></pre>
  <p><strong>Further explanation:</strong></p>
  <p>As you can see <code>admin_id=3</code> is excluded because I just dont want that one and whenever there is duplicate <code>country_id</code> between <code>admin_id = 92</code> and <code>$_Session['admin']['id'] = 5</code>, I keep the row with <code>admin_id = 92</code> .</p>