title: Oracle Select invalid identifier error from a table created with create as select statement
body: <p>I'm using Oracle 11g and I created a table B using a create as select statement.
  The creation was succeeded :</p>
  
  <p><code>create table B as select * from A;</code>  </p>
  
  <p>HOWEVER when a run a Select on specific columns of B I got an error ORA-00904 : "Mycolumn_C": invalid identifier.</p>
  
  <p>BUT when I run a select * from B , it works fine !</p>
  
  <p>The point is that "MyColum_C" is an alias in the select statement on table A , as follows :   </p>
  
  <pre><code>Create table B as select  code, name, useday as "Mycolum_C", validperiod as "Mycolum_D, enddate from A
  </code></pre>
  
  <p>For some reason,  select statement on newly created table B of those columns that had aliases on table A,  generates erro invalid identifier.  </p>
  
  <p>Examples of statements that fails :</p>
  
  <pre><code>Select Mycolum_C from B
  Select Mycolum_D from B
  </code></pre>
  
  <p>What is going on here ?</p>
  
  <p>Any help is very welcome ! </p>