如何在MYSQL中水平选择从最高到最低的顺序值

Question

这是我的表格标记

quiz_1_marks	quiz_2_marks	quiz_3_marks	quiz_4_marks
86.5	90.3	69.9	43.2
36.27	54.9	28.8	69.65

我想要选择这样的标记

max1	max2	max3	max4
90.3	86.5	69.9	43.2
69.65	54.9	36.7	28.8

Answer 1

使用条件聚合取消透视、排序、透视

select max1, max2, max3, max4
from tbl_marks
cross join lateral (
   select  
      max(case rn when 1 then qm end) max1,
      max(case rn when 2 then qm end) max2,
      max(case rn when 3 then qm end) max3,
      max(case rn when 4 then qm end) max4
   from (
      select q.m qm, row_number() over(order by q.m desc) rn
      from (
         select quiz_1_marks union all
         select quiz_2_marks union all
         select quiz_3_marks union all
         select quiz_4_marks
      ) q(m)
    ) t
 ) t;

见db<>fiddle