From: migurus@yahoo.com   
      
   On Wednesday, August 14, 2013 2:18:21 AM UTC-7, Ross Presser wrote:   
   > On Tuesday, August 13, 2013 9:43:44 PM UTC-4, migurus wrote:   
   >   
   > > I have a series of Customer ID / Date records showing participation of   
   customers on the daily basis. I need to find out how many new customers   
   participated each day.   
   >   
   > [snip]   
   >   
   > > Any ideas? I was trying to self-join but can not quite wrap my brain   
   around it.   
   >   
   > >   
   >   
   > > Thanks in advance.   
   >   
   >   
   >   
   > WITH X1 AS (   
   >   
   > SELECT ID, MIN(DT) AS FirstDT   
   >   
   > FROM @T AS T   
   >   
   > GROUP BY ID   
   >   
   > ),   
   >   
   > X2 AS (   
   >   
   > SELECT DISTINCT DT FROM @T AS T   
   >   
   > )   
   >   
   > SELECT X2.DT, COUNT(X1.ID)   
   >   
   > FROM X2   
   >   
   > LEFT JOIN X1 ON X2.DT = X1.FirstDT   
   >   
   > GROUP BY X2.DT   
   >   
   >   
   >   
   > DT   
   >   
   > ---------- -----------   
   >   
   > 2013-08-07 2   
   >   
   > 2013-08-08 0   
   >   
   > 2013-08-09 1   
   >   
   > 2013-08-12 0   
   >   
   > 2013-08-13 1   
   >   
   > Warning: Null value is eliminated by an aggregate or other SET operation.   
   >   
   >   
   >   
   > (5 row(s) affected)   
   >   
   >   
   >   
   > The value for 2013-08-09 is accurate; look closely at your data, 332551 is   
   represented twice on that day.   
      
   Thank you!   
   Works perfectly well.   
      
   --- SoupGate-Win32 v1.05   
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