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Need SQL help

Posted on 2011-03-23
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Last Modified: 2012-05-11
I am trying to write a sql statement perhaps CTE that will find the earliest contact_date or there is a diferrence between the episde dates of greater than six months. Should I do a stored procedure an break it up?    Here's what I have so far. Thanks

;with CTEMembersLBP as
 (SELECT *, row_number() over(partition by Pat_ID order by Pat_ID, contact_date asc) as Dup
FROM dbo.GR_LBP_DX_2010)
Delete from CTEmembersLBP where Dup > 1  
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Question by:Wonderwall
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Guy Hengel [angelIII / a3] earned 2000 total points
ID: 35202400
the ORDER BY does not need the Pat_ID ...

;with CTEMembersLBP as
 (SELECT *, row_number() over(partition by Pat_ID order by contact_date asc) as Dup
FROM dbo.GR_LBP_DX_2010)
Delete from CTEmembersLBP where Dup > 1  

apart from that, if you have a (clustered) index on Pat_ID + contact_date, this shall work best.

otherwise, if you really have to delete massive data, you might insert the data you want to retain into a temp table, truncate the original table, then insert back the data you want to retain from the temp table
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