title: SQL Converting a varchar to a clob within an SQL union
body: <p>Why does oracle not allow the following query</p>
  
  <pre><code>select to_clob(1) from dual
  union
  select wm_concat(sysdate) from dual;
  </code></pre>
  
  <p><code>wm_concat</code> returns a clob. To make both queries in the union have the same type columns i convert the column in the first query to a clob but Oracle gives me an <code>[1]: ORA-00932: inconsistent datatypes: expected - got CLOB</code> error even though both are returning a clob value. </p>
  
  <p>Each of the queries work individually and both return a clob value. </p>