SQL选择联接表

Question

If I have a table with the following data in MySQL:

id       Name       Value
1          A          4
1          A          5
1          B          8
2          C          9

how do I get it into the following format? is that even possible?

id         Column   Column   Column    Column   Column    Column
1            A        4         A        5         B        8
2            c        9

Answer 1

You can use conditional aggregation:

select id,
       max(case when seqnum = 1 then name end) as name_1,
       max(case when seqnum = 1 then value end) as value_1,
       max(case when seqnum = 2 then name end) as name_2,
       max(case when seqnum = 2 then value end) as value_2,
       max(case when seqnum = 3 then name end) as name_3,
       max(case when seqnum = 3 then value end) as value_3
from (select t.*,
             row_number() over (partition by id order by value) as seqnum
      from t
     ) t
group by id;