LeetCode: Students Report By Geography Posted on March 16, 2018July 26, 2020 by braindenny Students Report By Geography Similar Problems: CheatSheet: SQL & MySql CheatSheet: Leetcode For Code Interview CheatSheet: Common Code Problems & Follow-ups Tag: #sql A U.S graduate school has students from Asia, Europe and America. The students’ location information are stored in table student as below. | name | continent | |--------|-----------| | Jack | America | | Pascal | Europe | | Xi | Asia | | Jane | America | Pivot the continent column in this table so that each name is sorted alphabetically and displayed underneath its corresponding continent. The output headers should be America, Asia and Europe respectively. It is guaranteed that the student number from America is no less than either Asia or Europe. For the sample input, the output is: | America | Asia | Europe | |---------|------|--------| | Jack | Xi | Pascal | | Jane | | | Follow-up: If it is unknown which continent has the most students, can you write a query to generate the student report? Github: code.dennyzhang.com Credits To: leetcode.com Leave me comments, if you have better ways to solve. ## https://code.dennyzhang.com/students-report-by-geography select t1.name as America, t2.name as Asia, t3.name as Europe from (select (@cnt1 := @cnt1 + 1) as id, name from student cross join (select @cnt1 := 0) as dummy where continent='America' order by name) as t1 left join (select (@cnt2 := @cnt2 + 1) as id, name from student cross join (select @cnt2 := 0) as dummy where continent='Asia' order by name) as t2 on t1.id = t2.id left join (select (@cnt3 := @cnt3 + 1) as id, name from student cross join (select @cnt3 := 0) as dummy where continent='Europe' order by name) as t3 on t1.id = t3.id Post Views: 7