Return rows only if second column is different
<p>I have a table with a Customer number and a country. I need to return all customers that have different countries entered against each of them. That is, do not show me customers where the country values against them is the same for all records.</p>

<p>In the example below:</p>

<pre><code>╔══════════╦═════════╗
║ Customer ║ Country ║
╠══════════╬═════════╣
║      123 ║ USA     ║
║      123 ║ USA     ║
║      123 ║ UK      ║
║      456 ║ USA     ║
║      456 ║ USA     ║
║      789 ║ FRA     ║
║      789 ║ FRA     ║
║      789 ║ FRA     ║
╚══════════╩═════════╝
</code></pre>

<p>should return:</p>

<pre><code>╔══════════╗
║ Customer ║
╠══════════╣
║      123 ║
╚══════════╝
</code></pre>