sql server 中的索引/聚集索引结构

Question

我正在运行此报告：

use SalesDWH
go
;with
cte_biggie as(
select (c.npi+'|'+ CAST(DATEPART(yy, [DATE entered]) as varchar) +'|'+ 
CASE WHEN DATEPART(mm, [DATE entered]) = 01 THEN 'Jan' 
           WHEN DATEPART(mm, [DATE entered]) = 02 THEN 'Feb'
           WHEN DATEPART(mm, [DATE entered]) = 03 THEN 'Mar'
           WHEN DATEPART(mm, [DATE entered]) = 04 THEN 'Apr'
           WHEN DATEPART(mm, [DATE entered]) = 05 THEN 'May'
           WHEN DATEPART(mm, [DATE entered]) = 06 THEN 'Jun'
           WHEN DATEPART(mm, [DATE entered]) = 07 THEN 'Jul'
           WHEN DATEPART(mm, [DATE entered]) = 08 THEN 'Aug'
           WHEN DATEPART(mm, [DATE entered]) = 09 THEN 'Sep'
           WHEN DATEPART(mm, [DATE entered]) = 10 THEN 'Oct'
           WHEN DATEPART(mm, [DATE entered]) = 11 THEN 'Nov'
           WHEN DATEPART(mm, [DATE entered]) = 12 THEN 'Dec'
           END
           +'|'+isnull(cast(COUNT([specimen id]) as varchar),'') +'|'+isnull([practice name],'')+'|'+isnull(b.[mlis practice id],'')+'|'+a.[practice code]+'|'+[Requesting Physician]+'|'+isnull(c.salesrep,'')+'|'+
    isnull(cast(c.dateestablished as varchar),'')+'|'+ ISNULL (c.practiceaddress1,'')+'|'+ISNULL ( c.practiceaddress2 , '' )+'|'+ISNULL (c.practicecity,'')+'|'+ISNULL (c.practicestate,'')+'|'+
    ISNULL(b.[Active Inactive],'')) [result]
from quicklabdump a
    inner join qlmlismapping b
    on (b.[practice code] = a.[practice code])
    inner join PracticeandPhysician c
    on (a.[Requesting Physician]=c.doctorfirstname+' '+c.DOCTORLASTNAME
        and a.[practice code]=c.practicecode)
where   DATEPART(yy, [DATE entered]) in (2010,2011)
    and DATEPART(mm, [DATE entered]) in (01,02,03,04,05,06,07,08,09,10,11,12)

group by DATEPART(yy, [DATE entered]), DATEPART(mm, [DATE entered]), a.[practice name],b.[mlis practice id],a.[practice code],
    a.[Requesting Physician],c.salesrep,c.dateestablished, c.practicecity,c.practicestate,c.npi,c.practiceaddress1 ,c.practiceaddress2,
    b.[Active Inactive]


)
select 'NPI|Year Entered|Month Entered|Count|Practice Name|MLIS Code|Practice Code|Physician|Sales Rep|Date Established|Address|Address2|City|State|Status'
union all
select * from cte_biggie

因为我要加入 3 个表，所以我想知道使用索引和聚集索引优化此查询的最佳方法是什么。

我会在哪些列上添加索引？

目前此报告需要 20 秒。数据库大约有 5 个演出。

Answer 1

我要做的第一件事是更改 WHERE 子句 - 目前，它不是 sargable，这意味着即使在 Date Entered 列上有索引，它也不会被使用，因为您正在使用 DATEPART 函数它。

改为：

WHERE [Date Entered] >= '20100101' AND [Date Entered] < '20120101'

这将是我要更改的第一件事，并确保在输入的日期上有一个索引。这可能作为聚集索引是一个很好的竞争者，尽管如果不了解更多关于数据访问/加载模式等的信息，很难为整个环境选择最佳索引策略。

首先要检查的其他事项是在连接中涉及的其他表中的字段上设置索引。