select ç级,avg(table.ç§ç®1) as å«å ,avg(table.
ç§ç®2) as å«å2,...,
from 表å
group by ç级
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select ç级,avage(table.ç§ç®) as å«å,avage(ç§ç®2) as å«å2,count(*) as äººæ° from table groub by ç级