618. 学生地理信息报告

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max()函数的功效：(‘jack’, null, null)中得出’jack’,(null,null)中得出null. min()函数也可以。

select 
    max(if(continent='America',name,null)) America,
    max(if(continent='Asia',name,null)) Asia,
    max(if(continent='Europe',name,null)) Europe
from 
    (select *, row_number() over (partition by continent order by name) row_ from student) t
group by row_;