title: Firebird 2.5 Removing Rows with Duplicate Fields
body: <p>I am trying to removing duplicate values which, for some reason, was imported in a specific Table.
  There is no Primary Key in this table.
  There is 27797 unique records.</p>
  
  <pre><code>Select distinct txdate, plunumber from itemaudit
  </code></pre>
  
  <p>Give me the correct records, but only displays the txdate, plunumber of course.</p>
  
  <p>If it was possible to select all the fields but only select the distinct of txdate,plunumber I could export the values, delete the duplicated ones and re-import.
  Or if its possible to delete the distinct values from the entire table.</p>
  
  <p>If you select the distinct of all fields the value is incorrect.</p>