Subquery - how mysql merges multiple rows of data into multiple columns of one row

Question

The picture shows the data I filtered out. The statement is select time,wish_num,num from wish_num where time &gt;= '15296000' and time &lt;= '1495382399' group by time,wish_num, time and wish_num are joint primary keys. Now I hope Put the same date in...

怪我咯 · Answer

The simplest one is group_concat. If the poster doesn’t use it, then he has to use case when. Since the poster’s num after group by does not use an aggregate function, I understand that num has only one value? The sql is as follows

select time,
max(case when wish_num=1 then num else 0) '1',
max(case when wish_num=2 then num else 0) '2',
max(case when wish_num=5 then num else 0) '5',
max(case when wish_num=10 then num else 0) '10',
max(case when wish_num=20 then num else 0) '20'
from wish_num where time >= '15296000' and time <= '1495382399' group by time;