SELECT avg(revenue) ,  max(revenue) ,  sum(revenue) FROM manufacturers
Return the average, maximum, and total revenues across all manufacturers.
[Schema (values) (types)]: | manufactory_1 |  Manufacturers : code (text) , name (number) , headquarter (text) , founder (text) , revenue (text) | Products : code (text) , name (number) , price (text) , manufacturer (text);