title: In SSRS Need Optional Union Query or Equivalent
body: <p>I've inherited an SSRS report that doesn't work correctly. The report is a meta report of a document management system. FWIW, this is a monthly destruction report -- certain documents to be destroyed per retention policy. The kicker in this application is that there are special "stack_location" values that represent certain content status, e.g. 86/86/86 meaning document checked out but not returned. Any given document can have only one stack location, or one special stack location value. </p>
  
  <p>The basic query returned all the appropriate documents. The original designer, then created a filter list that excluded all the special values. This is as intended. However, the designer apparently assumed these special value exclusions could be toggled by clicking on a radio button in an options section. This, of course, does not work. Indeed, the whole approach seems off. </p>
  
  <p>I think I need a default query that includes an AND NOT IN ('86/86/86', '96/96/86'...), then somehow optional unions with the special values. I am completely at sea, however, on how to accomplish this. </p>
  
  <p>It seems it would be relatively straight forward if I were just using VB, or C#, to write different dynamic queries based on the value of a radio button. I am required, however, to use SSRS, technology I'm only vaguely familiar with. </p>
  
  <p>If anybody can point me in the right direction, I would be most appreciative. </p>
  
  <p>Thanks. </p>