title: mdx create new dimension from another one as substring
body: <p>I have the dimension 'Cities'.<br>
  Example:</p>
  
  <p>'Paris'
  'Moscow'
  'London'</p>
  
  <p>I need to create new Cities_Short_Name in <code>mdx</code> query where I can show first three letters. Examples: 'Par', 'Mos', 'Lon'. I can't change <code>DSV</code> on <code>SSAS</code>.</p>