title: Update table using alias
body: <p>I need to fill some fields in a table getting informations from other records of the same table.
  I tried to write a query to explain what I want to do:</p>
  
  <pre><code>update globale2
  set
    nita = t.nita,
    tita = t.tita,
    notaita = t.notaita
  where
    neng = t.neng and
    nita is null
    (select nita, neng, tita, notaita from globale where uris='mma' and nita is not null) as t
  </code></pre>
  
  <p>edit to eplain better:</p>
  
  <p>every records have these fields: "nita", "tita", "notaita", "neng" ("neng" cannot be null)</p>
  
  <p>I want to fill these fields: "nita", "tita", "notaita" (where "nita" is empty)
  with the same values from another record where "neng" equals the other "neng"</p>