res=driver.query(conn,"select count(*) count, avg(degree) as av, max(degree), min(degree) from thermometer where location='beijing' or location='tianjin' group by location, type")
res=driver.query(conn,"select count(*) as cnt, avg(degree) as av, max(degree), min(degree) from thermometer where location='beijing' or location='tianjin' group by location, type")
ifres.code~=0then
print("select from super table--- failed:"..res.error)