记一道群友的数据分析面试真题,你会吗?

统计与数据分析实战

共 1173字,需浏览 3分钟

 ·

2020-08-10 16:04

 近期在群里面看到了如下这样一个面试题目,这个题目其实难度不大,但是你是否能够很快写出这个答案来呢?



本文解答方案由群友老黄提供


老黄博客:https://blog.csdn.net/weixin_41261833/article/details/105739549?utm_source=app


建表语句

create table student (      id varchar(20),      name varchar(20),      gender char(1),      birth varchar(20),      department varchar(20),      address varchar(20)) charset = utf8;



插入数据

insert into student values("201901","张大佬","男","1985","计算机系","北京市海淀区"),("201902","郭大侠","男","1986","中文系","北京市昌平区"),("201903","张三","女","1990","中文系","湖南省永州市"),("201904","李四","男","1990","英语系","辽宁市阜新市"),("201905","王五","女","1991","英语系","福建省厦门市"),("201906","王六","男","1988","计算机系","湖南省衡阳市");



结果如下




第一步

select     department 院系,    case gender when "男" then 1 else 0 end 男,    case gender when "女" then 1 else 0 end 女from student;


结果如下




第二步

select       院系,      sum(男) 男,      sum(女) 女,      sum(男) + sum(女) as 总计from(    select department 院系,    case gender when "男" then 1 else 0 end 男,    case gender when "女" then 1 else 0 end 女    from student) agroup by 院系;



结果如下



怎么样,学会了吗?欢迎大家加群交流数分~


日常答疑|Python实现分类频数统计

日常答疑|Python处理时间格式并计算时间差值

浏览 36
点赞
评论
收藏
分享

手机扫一扫分享

分享
举报
评论
图片
表情
推荐
点赞
评论
收藏
分享

手机扫一扫分享

分享
举报