What procedures cost less than 5000 and have John Wen as a trained physician?
return procedures ;return costs of #1 ;return #1 where #2 is  lower than 5000 ;return physicians trained in #1 ;return #1 where #2 is  John Wen ;return #1 of both #3 and #5
['select', 'project', 'comparative', 'project', 'comparative', 'intersection']