如何在mysql中获得时间记录

Question

我需要在mysql中使用Time Wise Sales Report，我得到报告

Time    Amount
19:00:00    2
20:00:00    5
21:00:00    0
22:00:00    0
23:00:00    14

但我需要金额的总和

Time    Amount
19:00:00    2
20:00:00    5
21:00:00    5
22:00:00    5
23:00:00    14

这是我的查询

SELECT concat(MID(date_of_call, 12, 2),':00:00') TimeIntervel,COUNT(*) TotalEntries,date_format(date_of_call,'%d/%m/%Y') FROM ICC_MM_setup_suply 
WHERE DATE_FORMAT(date_of_call,'%d/%m/%Y')='31/01/2017'
GROUP BY concat(MID(date_of_call, 12, 2),':00:00')

Answer 1

您可以使用用户变量：

set @lastval := 0;    
select
    time,
    @lastval := if(Amount = 0, @lastval, Amount) Amount
from t
order by time;