Question

我有一些查询MySQL数据库的经验，我试图学习如何在Oracle中做同样的事情。理论上有多难。让我们说我有一个DEMOGRAPHICS表，其中包含以下列：DATE_OF_BIRTH，GENDER，RACE，ETHNICITY。还有一个CAR表，其中列有MAKE，列出了不同品牌的汽车（丰田，福特等）。我如何创建一个统计报告，列出每个汽车品牌和相应的百分比率列MALE，FEMALE，WHITE，ASIAN，BLACK，HISPANIC，NOT HISPANIC和两个年龄段列（18-30和50-70）。百分比应四舍五入到小数点后两位。它应该如下所示： enter image description here 我将不胜感激任何帮助，包括对类似查询的引用。谢谢！

Answer 1

需要更多信息。 WHITE，ASIAN，BLACK＆lt; ==这些都属于RACE专栏 HISPANIC，而不是HISPANIC＆lt; ==这些属于ETHNICITY专栏

Answer 2

 drop table demographics

 drop table car

 create table car(MAKE_ID number primary key, MAKE varchar2(30));

 create table demographics(DATE_OF_BIRTH date , GENDER varchar2(10), RACE varchar2(30), ETHNICITY varchar2(30), MAKE_ID references car);

 --insert into car table
 insert into car values(1,'Toyota');
 insert into car values(2,'Ford');
 insert into car values(3,'GM');

 --inserts 1000 rows into the demographics table
 insert into demographics
 select trunc(sysdate) - level as dob
        ,case when mod(level,2)=0 then 'MALE' else 'FEMALE' end as gender
        ,case when mod(level,2)=0 then 'WHITE' else 'BLACK' end as race
        ,case when mod(level,4)=0 then 'ASIAN'
              when mod(level,3)=0 then 'HISPANIC'
              when mod(level,2)=0 then 'NOT HISPANIC'
              else 'LATINO'
         end as ethnicity 
        ,case when mod(level,3)=0 then 3
              when mod(level,2)=0 then 2
              when mod(level,1)=0 then 1
         end as make_id     
 from dual
 connect by level<=1000;


 select make
        ,round((cnt_MAKE/tot_cnt)*100,2) as MALE_PERCENT
     ,round((cnt_MAKE/tot_cnt)*100,2) as FEMALE_PERCENT
 from(       
 select a.make
        ,count(case when b.gender ='MALE' then 1 end) as cnt_MALE
        ,count(case when b.gender ='FEMALE' then 1 end) as cnt_FEMALE
        ,count(case when b.race ='WHITE' then 1 end) as cnt_WHITE
        ,count(case when b.ethnicity ='ASIAN' then 1 end) as cnt_ASIAN
        ,count(case when  b.race ='BLACK' then 1 end) as cnt_BLACK
        ,count(case when b.ethnicity ='HISPANIC' then 1 end) as cnt_HISPANIC
        ,count(case when b.ethnicity ='NOT HISPANIC' then 1 end) as cnt_NOT_HISPANIC
        ,count(*) as tot_cnt        
   from car a
   join demographics b
     on a.make_id=b.make_id
 group by a.make  
 )

PL / SQL查询统计报告？

2 个答案: