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LeetCode 【困难】数据库-第618:学生地理信息报告(分组行列转换)

作者:互联网

题目要求

1. 按照’月份‘排序

select *,row_number() over (partition by continent order by name) rn from students;

2.行列转换,找出符合条件的一个人

select  
min(
case when continent = '一月' then name else  end)  as 一月,
min(
case when continent = '二月' then name else null end)  as 二月,
min(
case when continent = '三月' then name else null end)  as 三月,
min(
case when continent = '四月' then name else null end)  as 四月
from students;

3. 汇总集合

select  
min(
case when continent = '一月' then name else null end)  as 一月,
min(
case when continent = '二月' then name else null end)  as 二月,
min(
case when continent = '三月' then name else null end)  as 三月,
min(
case when continent = '四月' then name else null end)  as 四月
from (
select *,row_number() over (partition by continent order by name) rn from students
) b
group by rn;

标签:地理信息,end,name,min,when,618,LeetCode,else,continent
来源: https://www.cnblogs.com/Tdazheng/p/14962640.html