這個sql如何優化，，date條件放在最后，不想寫兩個條件。
select a.ALevel,count(1) HyCount,max(p.num) as Vnum
from _tmp_work a
left join (select count(DISTINCT videoName) as num,ALevel from _tmp_work
where date>='2020-7-1 00:00:00' and date<='2020-7-2 23:59:59'
group by alevel
) p on a.ALevel=p.ALevel
where a.date>='2020-7-1 00:00:00' and a.date<='2020-7-2 23:59:59'
group by a.ALevel
uj5u.com熱心網友回復：
我咋都覺得你那個left join 是多余的呢。select a.ALevel,count(1) HyCount,count(DISTINCT videoName) as Vnum
from _tmp_work a
where a.date>='2020-7-1 00:00:00' and a.date<='2020-7-2 23:59:59'
group by a.ALevel
轉載請註明出處，本文鏈接：https://www.uj5u.com/shujuku/239282.html
標籤：MySQL
上一篇：mysql主從復制有延遲，跪求