跪求sql大佬帮忙写个sql

Question

a              2021-04-11 12:54:56
b              2021-04-11 10:12:21
a              2021-04-11 02:25:36
b              2021-04-11 18:44:24
a              2021-04-06 12:20:10
b              2021-04-08 08:05:47
a              2021-04-07 15:25:36

Answer 1

select a,date_b,b from (select a,date(b) as date_b,b from 表 order by 1,2,3 desc) t group by 1,2;