mysql 统计

Mysql  /  houtizong 发布于 3年前   165

create table u(id int,name varchar(8),age int);mysql> select * from u;+------+--------+------+| id   | name   | age  |+------+--------+------+|    1 | tonny  |   18 ||    1 | wendy  |   30 ||    1 | james  |   25 ||    1 | simon  |   22 ||    1 | flynn  |   35 ||    1 | nancy  |   42 ||    1 | olivia |   51 ||    1 | linda  |   20 |+------+--------+------+8 rows in set (0.00 sec)

 

要求得到效果如下：
统计出不同年龄段的人数：

  年龄段 人数  
  18-20 2  
  21-30 3  
  31-40 1  
  41-50 1  
  > 50 1   

 

 

mysql> select elt(interval(age,18,21,31,41,51),    ->  '18-20',    ->  '21-30',    ->  '31-40',    ->  '41-50',    ->  '> 50'    -> ) as `年龄段`    -> ,count(*) as `人数`    -> from u    -> group by elt(interval(age,18,21,31,41,51),    ->  '18-20',    ->  '21-30',    ->  '31-40',    ->  '41-50',    ->  '> 50'    -> );+--------+------+| 年龄段 | 人数 |+--------+------+| 18-20  |    2 || 21-30  |    3 || 31-40  |    1 || 41-50  |    1 || > 50   |    1 |+--------+------+5 rows in set (0.03 sec)mysql>