code: def union_sql(view_name, *tables):
      
  
      if not tables:
          raise Exception("no tables given")
  
      ret = ""
      pre = "CREATE VIEW %s AS SELECT * FROM " % view_name
  
      for table in tables:
          ret += pre + table
          pre = " UNION SELECT * FROM "
  
      return ret
docs: This function generates string containing SQL code, that creates
      a big VIEW, that consists of many SELECTs.
  
      >>> utils.union_sql('global', 'foo', 'bar', 'baz')
      'CREATE VIEW global SELECT * FROM foo UNION SELECT * FROM bar UNION SELECT * FROM baz'