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          記一道群友的數(shù)據(jù)分析面試真題,你會嗎?

          共 1173字,需瀏覽 3分鐘

           ·

          2020-08-10 16:04

          ?近期在群里面看到了如下這樣一個面試題目,這個題目其實難度不大,但是你是否能夠很快寫出這個答案來呢?



          本文解答方案由群友老黃提供


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


          建表語句

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



          插入數(shù)據(jù)

          insert into student values("201901","張大佬","男","1985","計算機(jī)系","北京市海淀區(qū)"),("201902","郭大俠","男","1986","中文系","北京市昌平區(qū)"),("201903","張三","女","1990","中文系","湖南省永州市"),("201904","李四","男","1990","英語系","遼寧市阜新市"),("201905","王五","女","1991","英語系","福建省廈門市"),("201906","王六","男","1988","計算機(jī)系","湖南省衡陽市");



          結(jié)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;


          結(jié)果如下




          第二步

          select       院系,      sum(男) 男,      sum(女) 女,      sum(男) + sum(女) as 總計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;



          結(jié)果如下



          怎么樣,學(xué)會了嗎?歡迎大家加群交流數(shù)分~


          日常答疑|Python實現(xiàn)分類頻數(shù)統(tǒng)計

          日常答疑|Python處理時間格式并計算時間差值

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