title: How to apply multiple filters on TSQLQuery
body: <p>Singular filter on some column works, for example:</p>
  
  <pre><code>SQLQuery.Filter := 'ColumnName="some_filtered_text"'; // OK
  </code></pre>
  
  <p>But how to apply filter to many columns?</p>
  
  <p>For example this doesn't work:</p>
  
  <pre><code>SQLQuery.Filter := 'ColumnName1="some_filtered_text1",
      ColumnName2="some_filtered_text2"'; // Exception
  </code></pre>
  
  <p>It raises exception: "TApplication.HandleException Operator/function missing".</p>