title: Column not found when trying a cross database update in mysql
body: <p>I'm trying to copy the contents of a column in one mysql database to an identical table in another mysql database.</p>
  
  <p>I'm using:</p>
  
  <pre><code>UPDATE db1.table
  SET    db1.table.name = db2.table.name, 
         db1.table.address = db2.table.address
  WHERE  db1.table.id = db2.table.id;
  </code></pre>
  
  <p>I'm getting the error 1054: Unknown column 'db2.table.id' in 'where clause'.</p>
  
  <p>Both tables have an id column, so I'm not sure why it won't work. I'm logged in as admin, and have full rights to both databases.</p>