选择计数不同的慢 MSSQL

Question

您好，我在这里得到了一个简单的查询，但速度很慢，大约需要 40 秒才能取回数据，我尝试了不同的 SQL，但似乎仍然无法使其工作，任何建议都将不胜感激

select
  count (Distinct s.ExternalCustomerID) as PlayerCount,
  s.League  as Extra
from Q_Net_Ml_SportsDetailsActivity_monthly s with (nolock)
where  s.MerchantID = 584
  and s.WagerCount > 0
  and s.Year = 2021
group by League

计划： https://www.brentozar.com/pastetheplan/?id=HJ1bL0ivY

我试过这个：子查询

SELECT
    COUNT(ExternalCustomerID) AS Playercount,
    League AS extra
FROM (
    SELECT DISTINCT
      ExternalCustomerID,
      League
    FROM Q_Net_Ml_SportsDetailsActivity_monthly s with (nolock, INDEX(NCSI_Q_Net_Ml_SportsDetailsActivity_monthly))
    Where  s.MerchantID = 584
      and s.WagerCount > 0
      and s.Year = 2021
) dt
GROUP BY League

似乎仍然很慢 https://www.brentozar.com/pastetheplan/?id=HkAHjCswY

Answer 1

可能会尝试在您的表“Q_Net_Ml_SportsDetailsActivity_monthly”中放置一些索引，这些索引位于选择语句中使用的列中。然后尝试再次运行查询。