#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;