Oracle

Question

我有 table 列 Date 和时间戳，以秒为单位的值并且有类似

的查询

Table

2017-01-10 06:45:00 PM  1119
2017-01-10 03:30:00 PM  1054
2017-01-11 11:15:00 PM  379
2017-01-10 06:30:00 PM  377
2017-01-11 09:15:00 PM  375

查询

SELECT 
  TO_char(DtTm,'YYYY-MM-DD hh:mi:ss AM') As DataDt,      
  max(MaxSec) as Wait_sec, DtTimeTable.HrID,
FROM DtTimeTable 
WHERE  DtTimeTable.HrName in ('Dept1', 'Dept2', 'Dept3')
AND  DtTm BETWEEN to_date('2017-01-08 00:00:00', 'YYYY-MM-DD hh24:mi:ss') 
AND to_date('2017-01-10 23:59:59', 'YYYY-MM-DD hh24:mi:ss')
Group by TO_char(DtTm,'YYYY-MM-DD hh:mi:ss AM'),DtTimeTable.HrID 
order by Wait_sec desc

这给了我所有记录，如果我添加

select * from
Query1 --(above)
where rownum <1 order by Wait_sec desc, Datadt desc;

我只得到结果集的最高值

如何获取每个日期的 DatewithTime、Maxvalue

2017-01-10 06:45:00 PM  1119
2017-01-11 11:15:00 PM  379

Answer 1

尝试这样的事情：

Select *
From (
    Select t.*,
      Row_number() over(partition by trunc(datecol) order by value desc nulls last) rn
    From yourtable t
) where rn = 1;

它根据您的值列的降序在日期内分配行号，然后过滤以获取第一行

Answer 2

下面的解决方案使用分组、MAX() 聚合函数和 FIRST/LAST 函数（使用 KEEP DENSE_RANK）。如果某个日期多次达到相同的最高值，它会选择当天第一次达到该值的时间。

with
     test_data( dt, val ) as (
       select to_date('2017-01-10 06:45:00 PM', 'yyyy-mm-dd hh:mi:ss AM'), 1119 from dual 
       union all
       select to_date('2017-01-10 03:30:00 PM', 'yyyy-mm-dd hh:mi:ss AM'), 1054 from dual 
       union all
       select to_date('2017-01-11 11:15:00 PM', 'yyyy-mm-dd hh:mi:ss AM'),  379 from dual 
       union all
       select to_date('2017-01-10 06:30:00 PM', 'yyyy-mm-dd hh:mi:ss AM'),  377 from dual 
       union all
       select to_date('2017-01-11 09:15:00 PM', 'yyyy-mm-dd hh:mi:ss AM'),  375 from dual
     )
--  end of test data; SQL query begins below this line (use actual table and column names)
select min(dt) keep(dense_rank last order by val) as dt, max(val) as val
from   test_data
group by trunc(dt)
order by dt   --  if needed
;

DT                            VAL
---------------------- ----------
2017-01-10 06:45:00 PM       1119
2017-01-11 11:15:00 PM        379

2 rows selected.

Oracle - date/time 每个日期的最大值

Oracle - Max value from each date with date/time

sql

greatest-n-per-group