Predict output for ROUND function

• dutt

  SSC Eights!

  Points: 862

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  February 17, 2010 at 4:32 am

  #74216

  Predict output for ROUND function

  This is the QotD in SQL Server Central only. I did not understand the solution. Could anyone elaborate it.

  What are the outputs?

  DECLARE @round1 float

  SET @round1 = 165.755

  SELECT ROUND(@round1,2)

  DECLARE @round2 float

  SET @round2 = 165.555

  SELECT ROUND(@round2,2)

  Correct answer:

  165.75 and 165.56

  Explanation:

  A float, without the size defined , is defaulted to a float(53), which is an 8 byte double precision. If I change the variables to anything from float(25) to float(53), I get the wrong answer (75.42). If i use flat(24) or less, I get the correct answer.

  Use CAST operator to get proper the results. Example: SELECT ROUND(CAST(@round1 AS DECIMAL(15,3)),2)

  And again if we try this,

  DECLARE @round1 float(25)

  SET @round1 = 165.7555

  SELECT ROUND(@round1,3)

  DECLARE @round2 float(25)

  SET @round2 = 165.5555

  SELECT ROUND(@round2,3)

  The answer is 165.756, 165.555

• DBA_Dom

  SSCrazy

  Points: 2902

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  February 19, 2010 at 12:31 pm

  #1122062

  I want to say that this is because of the repeating '5' three times.