title: Input validation - what is wrong with this query?
body: <p>I try to create validation in APEX.
  So in Page Designer I go to "Processing=>Validations". I create new and select "SQL Expression"
  Then I type SQL:</p>
  
  <pre><code>SELECT article_no FROM dade_dict_articles WHERE article_no = :P11_ARTICLE_NO
  </code></pre>
  
  <p>But I get error:</p>
  
  <pre><code>ORA-06550: line 1, column 30: ORA-00936: missing expression
  </code></pre>
  
  <p>I try SQL without variable, just:</p>
  
  <pre><code>SELECT article_no FROM dade_dict_articles WHERE article_no = 456785
  </code></pre>
  
  <p>Same error.
  I try this SQL in SQL Developer - of course it works. What is wrong?</p>