Question

我在下面有这个极其冗长的问题。我遇到了运行它的问题，因为它需要永远，并且不断超时：

    with t as 
   (
select a.ID, 
       a.Date_Reported AS [Date Sent],  
       b.Date_Received AS [Date Returned], 

(datediff(dd, a.date_reported, b.date_received) 
      + CASE WHEN Datepart(dw, b.date_received) = 7 THEN 1 ELSE 0 END 
       - (Datediff(wk, a.date_reported, b.date_received) * 2 ) 
       - CASE WHEN Datepart(dw, b.date_received) = 1 THEN 1 ELSE 0 END + 
       - CASE WHEN Datepart(dw, b.date_received) = 1 THEN 1 ELSE 0 
       END) AS [Overall_Time_Spent]

from [Transactions_External] a 
join [Transactions] b on b.id like '%'+a.id+'%'
where a.customer = 'AA'
AND a.Date_Reported >= DATEADD(MONTH,-1,DATEADD(MONTH,DATEDIFF(MONTH,0,GETDATE()),0))
AND a.Date_Reported <  DATEADD(d,1,EOMONTH(GETDATE(),-1)) 
AND a.ID IS NOT NULL
AND a.ID <> ''
AND b.ID not like '%_H'

    )


    select V.*
    from 
    (
        select 
           sum(case when Overall_Time_Spent < 0 then 1 else 0 end) as Errors,
           sum(case when Overall_Time_Spent between 0 and 3 then 1 else 0 end) as _0_3_days,
           sum(case when Overall_Time_Spent = 4 then 1 else 0 end) as _4_days,
           sum(case when Overall_Time_Spent = 5 then 1 else 0 end) as _5_days,
           sum(case when Overall_Time_Spent between 6 and 8 then 1 else 0 end) as _6_8_days,
           sum(case when Overall_Time_Spent >= 9 then 1 else 0 end) as more_than_9_days,
           count(Overall_Time_Spent) as Total
    from t

    ) T1
    cross apply 
    ( values 
      ('Count', convert(int, [Errors]), convert(int, [_0_3_days]), convert(int, [_4_days]), convert(int, [_5_days]), convert(int, [_6_8_days]),  convert(int, [more_than_9_days]), convert(int, [Total]))
      )
    v([Time Taken (days)], [Errors], [0-3],[4],[5],[6-8],[9+], [Total])

查询基本上是查看两个表，加入id（在任一个表上略有不同，因此在连接上类似），然后在两个日期中找到差异以查找花费的总时间。然后在时间被分成范围。该查询仅限于上个月。

我可以采取哪些措施来加快运行速度或更改查询以帮助其更快地运行。我认为问题可能出在最初的选择中：

datediff(dd, a.date_reported, b.date_received) 
      + CASE WHEN Datepart(dw, b.date_received) = 7 THEN 1 ELSE 0 END 
       - (Datediff(wk, a.date_reported, b.date_received) * 2 ) 
       - CASE WHEN Datepart(dw, b.date_received) = 1 THEN 1 ELSE 0 END + 
       - CASE WHEN Datepart(dw, b.date_received) = 1 THEN 1 ELSE 0 
       END) AS [Overall_Time_Spent]

我可能会选择所有数据库而不是上个月？

需要注意的一件重要事情是我无法创建任何表格或拆分查询 - 所以我真的需要运行选择并在一个查询中执行。我不确定这是可能的。

Answer 1

加入喜欢和＆＃34;％＆＃34;首先不推荐

join [Transactions] b on b.id like '%'+a.id+'%'

索引不会在a.id（如果有）上使用，而且需要完全扫描。也许尝试对您的查询进行解析以查看扫描的行数

简化查询以使其运行更快

1 个答案: