title: Index on two concatenated columns SQL
body: <p>Is there a way to create an index on a concatenated column? for example:</p>
  
  <p>Having a query like the following</p>
  
  <pre><code>SELECT * 
  FROM my_table 
  WHERE name + lastname = 'hola mundo'`
  </code></pre>
  
  <p>how can I improve the search result applying indexes? </p>
  
  <p>PD: my actual query is not as simple as that, but the <code>WHERE</code> part using <code>col1 + col2 = result</code> is the one that slow everything. Usually my query takes 1 second when doing something like <code>WHERE col1 = 'hola' and col2 = 'mundo'</code> but when <code>WHERE col1 + col2 = 'hola mundo'</code> it takes 5 or 6 seconds.</p>