mysql单列值到多列组由另一个列值

Question

我正在尝试从这样的表创建查询

timestamp             |         iddebi       | value 
========================================================
2018-02-17  14:29:00             1               901
2018-02-19  14:29:00             1               501
2018-02-20  14:29:00             1               301
2018-02-21  14:29:00             1               501
2018-02-18  14:29:00             2               301
2018-02-19  14:29:00             2               401
2018-02-20  14:29:00             2               601
2018-02-21  14:29:00             2               701
2018-02-18  14:29:00             3               901
2018-02-19  14:29:00             3               501
2018-02-20  14:29:00             3               301
2018-02-21  14:29:00             3               501

我想选择日期之间的值，按日期对它们进行分组，并在分隔的列上放置 id

timestamp            |  iddebi_1  |  iddebi_2  | iddebi_3
===========================================================
2018-02-17  14:29:00     901         null        null
2018-02-18  14:29:00     null         301        901
2018-02-19  14:29:00     501         401        501
2018-02-20  14:29:00     301         601        301
2018-02-21  14:29:00     501         701        501

所以，我希望不同 id 的值按列分组(基于 id )没有值的地方返回null谢谢你们

Answer 1

select timestamp,
       max(case when iddebi = 1 then value else null end) as iddebi_1,
       max(case when iddebi = 2 then value else null end) as iddebi_2,
       max(case when iddebi = 3 then value else null end) as iddebi_3
from your_table
group by timestamp