Question

我从表中的第一个查询大约需要40秒，并创建超过80,000行。我想通过Site，Sequence，Total和任何操作系统版本来获取Windows 7应用程序的数量。

这些子查询有效，但当然它们会大大减慢这个过程。运行需要3.5小时。

有更有效的方法吗？

输出：

SoftwareName    Sequence    Site    Win7/site       Win7Installs/seq    TotWin7apps TotalInstalls
Adobe Acrobat       1       BKN         1                   5               626         7854
AutoCAD LT          1       BKN         1                   1               3           15
Adobe Acrobat       1       CTW         4                   5               626         7854
Adobe Captivate     1       CTW         1                   1               8           60

查询：

WITH PCapps AS (
SELECT DISTINCT
    Computer,
    Sequence,
    Site,
    SoftwareName,
    OS
FROM table
)

SELECT DISTINCT
    SoftwareName,
    Sequence,
    Site,
    (SELECT COUNT(p1.SoftwareName) FROM PCapps p1 WHERE p1.SoftwareName = pc.Softwarename AND OS = 'Windows 7 Enterprise' AND p1.Site = pc.Site) as 'Win7/site',
    (SELECT COUNT(p1.SoftwareName) FROM PCapps p1 WHERE p1.SoftwareName = pc.Softwarename AND OS = 'Windows 7 Enterprise' AND p1.Sequence = pc.Sequence) as 'Win7Installs/seq',
    (SELECT COUNT(p2.SoftwareName) FROM PCapps p2 WHERE p2.SoftwareName = pc.Softwarename AND OS = 'Windows 7 Enterprise') as TotWin7apps,
    (SELECT COUNT(p3.SoftwareName) FROM PCapps p3 WHERE p3.SoftwareName = pc.SoftwareName) as TotalInstalls 
    FROM PCapps pc

**更新：

使用@Jason Carter的提示，我创建了几个#temp表并加入它们。结果在不到一分钟的时间内运行得非常快（不比初始查询长很多）。这个方法与@ JasonCarter的解决方案略有不同，因为我按照他的初始提示创建了#temp表。我创建了几个#temp表，每个表都包含COUNT（）s。

SELECT DISTINCT
    Computer,
    Sequence,
    Site,
    SoftwareName,
    OS
INTO #PCapps
      FROM TABLE    

SELECT
    SoftwareName,
    Site,
    COUNT(SoftwareName) AS [SiteInstalls]
INTO #SiteInstalls
FROM #PCapps 
    WHERE OS = 'Windows 7 Enterprise'
    GROUP BY Site, SoftwareName

SELECT
    SoftwareName,
    Sequence,
    COUNT(SoftwareName) AS [SeqInstalls]
INTO #SeqInstalls
FROM #PCapps
    WHERE OS = 'Windows 7 Enterprise'
    GROUP BY Sequence, SoftwareName

SELECT
    SoftwareName,
    COUNT(SoftwareName) AS [Win7Installs]
INTO #Win7Installs
FROM #PCapps
    WHERE OS = 'Windows 7 Enterprise'
    GROUP BY SoftwareName

SELECT
    SoftwareName,
    COUNT(SoftwareName) AS [AppInstalls]
INTO #AppInstalls
FROM #PCapps
    GROUP BY SoftwareName   

SELECT
    pc.SoftwareName,
    pc.Sequence,
    pc.Site,
    sit7.SiteInstalls,
    seq7.SeqInstalls,
    w7.Win7Installs,
    ai.AppInstalls
    FROM #PCapps pc
    LEFT OUTER JOIN #SiteInstalls sit7 ON sit7.SoftwareName = pc.SoftwareName AND sit7.Site = pc.Site
    LEFT OUTER JOIN #SeqInstalls  seq7 ON seq7.SoftwareName = pc.SoftwareName AND seq7.Sequence = pc.Sequence
    LEFT OUTER JOIN #Win7Installs w7   ON   w7.SoftwareName = pc.SoftwareName
    LEFT OUTER JOIN #AppInstalls ai    ON   ai.Softwarename = pc.SoftwareName

DROP TABLE #PCapps
DROP TABLE #SiteInstalls
DROP TABLE #SeqInstalls
DROP TABLE #Win7Installs
DROP TABLE #AppInstalls

Answer 1

我会先尝试将子查询运行到临时表中以收集计数，然后提取总计数。通过查询设置的方式，它将为每个PCapps行运行每个子查询一次，这就是为什么它需要这么长时间。

尝试这样的事情：

declare @t table (Computer varchar(10), Sequence int, Site varchar(3), SoftwareName varchar(20), OS varchar(20) )

insert into @t values
 ('C1',1,'BKN','Adobe Acrobat','Win7')
,('C2',1,'BKN','Adobe Acrobat','Win7')
,('C3',1,'BKN','Adobe Acrobat','Win7')
,('C1',1,'BKN','AutoCAD LT ','Win7')
,('C3',1,'BKN','AutoCAD LT ','Win7')
,('B1',2,'CTW','Adobe Acrobat','Win7')
,('B2',2,'CTW','Adobe Acrobat','Win7')
,('B3',3,'CTW','Adobe LT','Win7')
,('B4',3,'CTW','Adobe Acrobat','Win7')
,('A1',2,'CTW','Adobe Acrobat','Win7')
,('A2',2,'CTW','Adobe LT','Win7')
,('A3',2,'CTW','Adobe Acrobat','Win7')
,('X4',3,'CTW','Adobe Acrobat','WinXP')
,('X1',2,'CTW','Adobe Acrobat','WinXP')
,('X2',2,'CTW','Adobe LT','WinXP')
,('X3',2,'CTW','Adobe Acrobat','WinXP')
,('A4',2,'CTW','Adobe Acrobat','Win7');

SELECT 
    Site,
    OS,
    SoftwareName, 
    Sequence,
    COUNT(SoftwareName)  as 'Count'
into #SiteSpecific
FROM @t
group by Site, OS, SoftwareName, Sequence;


WITH PCapps AS (
SELECT DISTINCT
    Computer,
    Sequence,
    Site,
    SoftwareName,
    OS
FROM @t
)
SELECT 
    DISTINCT
    PC.SoftwareName,
    PC.Sequence,
    PC.Site,
    PerSeq.[Count] as 'Win7Installs/seq',
    PerSite.[Count] as TotWin7apps,
    total.[Count] as TotalInstalls 
FROM PCapps pc
inner join (select SoftwareName, Sequence, OS, sum([Count]) [Count] from #SiteSpecific group by SoftwareName, Sequence, OS) PerSeq 
    on PerSeq.SoftwareName = pc.Softwarename 
    AND PerSeq.Sequence = pc.Sequence
    AND PerSeq.OS = pc.OS
inner join (select SoftwareName, Site, OS, sum([Count]) [Count] from #SiteSpecific group by SoftwareName, Site, OS) PerSite 
    on PerSite.SoftwareName = pc.Softwarename 
    AND PerSite.Site = pc.Site
    AND PerSite.OS = pc.OS
inner join (select SoftwareName, sum([Count]) [Count] from #SiteSpecific group by SoftwareName) Total 
    on Total.SoftwareName = pc.Softwarename 
where Pc.OS='Win7'
order by SoftwareName, Sequence, Site

Answer 2

对我来说真的很奇怪......优化器利用并行性来使子查询非常高效。我填写了一个有120K记录的虚拟表，并尝试了下面的内容。第三个查询只比第一个查询（你的）略高一些，但代价是更复杂。我会原样离开你的。可能有一个更好的解决方案，但你的看起来不错。你需要多长时间来处理80K行？

WITH PCapps2 AS (
SELECT DISTINCT
    Computer,
    Sequence,
    Site,
    SoftwareName,
    OS
FROM pcapps
)
SELECT DISTINCT
    SoftwareName,
    Sequence,
    Site,
    (SELECT COUNT(p1.SoftwareName) FROM PCapps2 p1 WHERE p1.SoftwareName = pc.Softwarename AND OS = 'Windows 7 Enterprise' AND p1.Site = pc.Site) as 'Win7/site',
    (SELECT COUNT(p1.SoftwareName) FROM PCapps2 p1 WHERE p1.SoftwareName = pc.Softwarename AND OS = 'Windows 7 Enterprise' AND p1.Sequence = pc.Sequence) as 'Win7Installs/seq',
    (SELECT COUNT(p2.SoftwareName) FROM PCapps2 p2 WHERE p2.SoftwareName = pc.Softwarename AND OS = 'Windows 7 Enterprise') as TotWin7apps,
    (SELECT COUNT(p3.SoftwareName) FROM PCapps2 p3 WHERE p3.SoftwareName = pc.SoftwareName) as TotalInstalls 
    FROM PCapps2 pc

;WITH PCapps2 AS (
SELECT DISTINCT
    Computer,
    Sequence,
    Site,
    SoftwareName,
    OS
FROM pcapps
)
SELECT DISTINCT
    SoftwareName,
    Sequence,
    Site,
    COUNT(case when os = 'Windows 7 Enterprise' then 1 end) over (partition by pc.Softwarename,pc.Site) as 'Win7/site',
    COUNT(case when os = 'Windows 7 Enterprise' then 1 end) over (partition by pc.Softwarename,pc.Sequence) as 'Win7Installs/seq',
    COUNT(case when os = 'Windows 7 Enterprise' then 1 end) over (partition by pc.Softwarename) as TotWin7apps,
    COUNT(*) over (partition by pc.Softwarename) as TotalInstalls
    FROM PCapps2 pc

;WITH PCapps2 AS (
SELECT DISTINCT
    Computer,
    Sequence,
    Site,
    SoftwareName,
    OS
FROM pcapps
), a as (
    select softwarename, site, COUNT(*) as 'Win7/site'
    from pcapps2
    where os = 'Windows 7 Enterprise'
    group by softwarename, site
), b as (
    select softwarename, sequence, COUNT(*) as 'Win7Installs/seq'
    from pcapps2
    where os = 'Windows 7 Enterprise'
    group by softwarename, sequence
), c as (
    select softwarename, COUNT(case when os = 'Windows 7 Enterprise' then 1 end) as TotWin7apps, COUNT(*) as TotalInstalls
    from pcapps2
    group by softwarename
), d as (
    select distinct softwarename, sequence, site
    from    pcapps2
)
select d.*, isnull(a.[Win7/site], 0) as [Win7/site], isnull(b.[Win7Installs/seq],0) as [Win7Installs/seq] 
        , isnull(c.TotWin7apps,0) as TotWin7apps, isnull(c.TotalInstalls, 0) as TotalInstalls  
from    d
        left join a on d.softwarename = a.softwarename and d.site = a.site 
        left join b on d.softwarename = b.softwarename and d.sequence = b.sequence 
        left join c on d.softwarename = c.softwarename

首先查询：表'pcapps'。扫描计数15，逻辑读取6630，物理读取0，预读取读取0，lob逻辑读取0，lob物理读取0，lob预读读取0。表'工作台'。扫描计数0，逻辑读取0，物理读取0，预读取读取0，lob逻辑读取0，lob物理读取0，lob预读读取0。

第二个查询：表'pcapps'。扫描计数3，逻辑读取1326，物理读取0，预读取读取0，lob逻辑读取0，lob物理读取0，lob预读读取0。表'工作台'。扫描计数18，逻辑读取1983591，物理读取0，预读读取0，lob逻辑读取0，lob物理读取0，lob预读读取0。

第三个查询：表'pcapps'。扫描计数12，逻辑读取5304，物理读取0，预读取读取0，lob逻辑读取0，lob物理读取0，lob预读取读取0。表'工作台'。扫描计数0，逻辑读取0，物理读取0，预读取读取0，lob逻辑读取0，lob物理读取0，lob预读读取0。

优化子查询的性能

2 个答案: