题解 | 考试分数(一)
考试分数(一)
https://www.nowcoder.com/practice/f41b94b4efce4b76b27dd36433abe398
select job,round(avg(score),3) as avg from grade group by job order by avg desc
纠结group by用还是不用?
当需要考虑“每类、各个”等词时
核心:需要把表按相同的类别合并成一行,并分组计算时
用group by
考试分数(一)
https://www.nowcoder.com/practice/f41b94b4efce4b76b27dd36433abe398
select job,round(avg(score),3) as avg from grade group by job order by avg desc
纠结group by用还是不用?
当需要考虑“每类、各个”等词时
核心:需要把表按相同的类别合并成一行,并分组计算时
用group by
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