get previous value

• ekknaveen

  SSCrazy

  Points: 2317

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  September 13, 2013 at 1:09 am

  #104214

  Hi,

  I am having the below records

  Date value

  01-01-2013 10

  02-01-2013 20

  03-01-2013 0

  04-01-2013 0

  05-01-2013 30

  06-01-2013 40

  07-01-2013 0

  08-01-2013 50

  I want to display the value 20 for the dates 3rd and 4th and value 40 for the date 07th.

  In general, for any date if the value is 0 then get the privoud non zero value.

  Can anyone pls help me to get this one

  Thanks

  Naveen

• ChrisM@Work

  SSC Guru

  Points: 186127

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  September 13, 2013 at 2:00 am

  #1649979

  ;WITH SampleData (Date, value) AS (

  SELECT '01-01-2013', 10 UNION ALL

  SELECT '02-01-2013', 20 UNION ALL

  SELECT '03-01-2013', 0 UNION ALL

  SELECT '04-01-2013', 0 UNION ALL

  SELECT '05-01-2013', 30 UNION ALL

  SELECT '06-01-2013', 40 UNION ALL

  SELECT '07-01-2013', 0 UNION ALL

  SELECT '08-01-2013', 50

  )

  SELECT s.[Date], value = ISNULL(NULLIF(s.value,0), x.value)

  FROM SampleData s

  CROSS APPLY (

  SELECT TOP 1 si.value

  FROM SampleData si

  WHERE si.[Date] <= s.[Date]

  AND si.value > 0

  ORDER BY si.[Date] DESC

  ) x

  ORDER BY s.[Date]

  ^{“Write the query the simplest way. If through testing it becomes clear that the performance is inadequate, consider alternative query forms.” - Gail Shaw}

  For fast, accurate and documented assistance in answering your questions, please read this article.
  Understanding and using APPLY, (I) and (II) Paul White
  Hidden RBAR: Triangular Joins / The "Numbers" or "Tally" Table: What it is and how it replaces a loop Jeff Moden