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POOptimize performance of sub-queries
 

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    <p>My first query from table takes about 40 seconds and creates over 80,000 rows. I want to get the counts of Windows 7 applications by Site, Sequence, Total and any OS version.</p> <p>These sub-queries work, but of course they slow the process down considerably. It took 3.5 hours to run.</p> <p>Is there a more efficient way to do this?</p> <p>Output:</p> <pre><code>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 </code></pre> <p>Query:</p> <pre><code>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 </code></pre> <p>** UPDATE:</p> <p>Using the tips from @Jason Carter, I created a few #temp tables and join them. The result runs very fast in less than a minute (not much longer than the initial query). This method is slightly different than @JasonCarter's solution as I was following his initial tip to create #temp tables. I created several #temp tables, each including the COUNT()s.</p> <pre><code>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 </code></pre>
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