title: sqlalchemy INSERT from SELECT
body: <p>I have a trouble. 
  The INSERT from SELECT construction compiles, but not performed. There aren't any error. If look to the log file, you won't SQL like ISERT INTO ... SELECT ... FROM ....</p>
  
  <p>This is is my code:</p>
  
  <pre><code>    DBSession.query(ProductMediaGalleryArchive)\
          .filter(ProductMediaGalleryArchive.product_id.in_(pack))\
          .delete(synchronize_session=False)
  
      query = DBSession.query(
              ProductMediaGallery.code,
              ProductMediaGallery.filename,
              ProductMediaGallery.mimetype,
              ProductMediaGallery.sha1hash,
              ProductMediaGallery.position,
              ProductMediaGallery.excluded,
              ProductMediaGallery.created,
              ProductMediaGallery.updated,
              ProductMediaGallery.id,
              ProductMediaGallery.is_rollover,
              Product.code.label('product_code'),
          ).join((Product, Product.id==ProductMediaGallery.product_id))\
          .filter(ProductMediaGallery.product_id.in_(pack))
  
      insert(ProductMediaGalleryArchive).from_select(
          (
              ProductMediaGalleryArchive.code,
              ProductMediaGalleryArchive.filename,
              ProductMediaGalleryArchive.mimetype,
              ProductMediaGalleryArchive.sha1hash,
              ProductMediaGalleryArchive.position,
              ProductMediaGalleryArchive.excluded,
              ProductMediaGalleryArchive.created,
              ProductMediaGalleryArchive.updated,
              ProductMediaGalleryArchive.id,
              ProductMediaGalleryArchive.is_rollover,
              ProductMediaGalleryArchive.product_code
          ),
          query
      )
  </code></pre>
  
  <p>Anybody know why doesn't performed it?</p>