mysql之count,max,min,sum,avg,celing，floor

MAX

1、最大的id

1 use school;
2 select max(id) from tb_student;

Min

1、最小id

use school;
select min(id) from tb_student;

SUM

1、求出所有学生的年龄和

use school;
select sum(age) from tb_student;

AVG

1、求所有学生的年龄平均值

use school;
select avg(age) from tb_student;

celing

celing翻译过来就是“天花板”的意思，意思就是，不管小数点后面是什么，就往上进位。比如上面的年龄平均值

use school;
select ceiling(avg(age))  from tb_student;

当然和天花板对应的还有floor函数，当然意思就是相反的了。

floor

use school;
select floor(avg(age))  from tb_student;

mysql之count,max,min,sum,avg,celing，floor

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