1
所以我在MySQL中有一個表PowerUse。它有兩個重要的列,ID(long int)和timeRecorded(timeStamp)。條目之間通常有很長的時間差距。我的目標是查詢表格以得到一個結果,告訴我在20分鐘內每分鐘有多少記錄 - 包括沒有記錄的分鐘的0響應。SQL JOIN語法問題
感謝MySQL: Select All Dates In a Range Even If No Records Present我已經到了下面的查詢,但我不能得到dratted的工作。有人能指出我正在製造的明顯錯誤,所以我可以停止將我的頭撞在磚牆上嗎?我知道它在JOIN中,我看不到它。謝謝!
select count(PowerUse.id) + 0 as counter, timestamp((PowerUse.timeRecorded div 100)*100) as time
from PowerUse right join
(
select date_add(NOW(), INTERVAL -n2.num*10-n1.num MINUTE) as dateb from
(select 0 as num
union all select 1
union all select 2
union all select 3
union all select 4
union all select 5
union all select 6
union all select 7
union all select 8
union all select 9) n1,
(select 0 as num
union all select 1
union all select 2
) n2
as) datea
on (timestamp(PowerUse.timeRecorded div 100)*100) = dateb.datea
group by timeRecorded div 100 ;