#求对应的平均值
#SELECT job,AVG(score,3) FROM grade GROUP BY job ORDER BY score DESC;

#求对应的平均值,且保留三位小数
#SELECT job,CAST(AVG(score) AS DECIMAL(10,3)) FROM grade GROUP BY job ORDER BY score DESC;

#四舍五入
SELECT job,ROUND(AVG(score),3) FROM grade GROUP BY job ORDER BY score DESC;

#多了一个逗号
#SELECT job,FORMAT(AVG(score),3) FROM grade GROUP BY job ORDER BY score DESC;