## Round real Value withoot truncation

 Author Message idrisgani Grasshopper Group: General Forum Members Points: 19 Visits: 22 Hi,I want to perform the following steps 1. Convert the real number into a character. 2. Convert the resulting character to a decimal. 3. Round the value at the N+1 th place.My requirement isWhen n=2I want to round 18.005 to 18.01 or 18.0049 to 18.00(at 100th place)when i try with Declare @real realSet @real=18.005print Round(Convert(Decimal(15,7),Convert(varchar(30),@real)),2)i can able to get the result until i get some indefinite real value like -4.8892562E-08. so when i try the same logic, i am getting a conversion error(Error converting data type varchar to numeric.). Please help me to get the problem resolved. thanks in advance Randolph West Old Hand Group: General Forum Members Points: 322 Visits: 431 You're going to run into that problem because of the rule for the floating point. How about converting to decimal(38,17) from real before trying to cast it out to a varchar?Alternatively, do this in code. SwePeso SSCrazy Group: General Forum Members Points: 2731 Visits: 3431 `DECLARE @n TINYINTSET @n = 2DECLARE @Sample TABLE ( Value DECIMAL(15, 7) )INSERT @SampleSELECT 18.0049 UNION ALLSELECT 18.005SELECT Value, ROUND(Value + CAST(0.5E * POWER(0.1E, @n) AS DECIMAL(15, 7)), @n, 1)FROM @Sample` N 56°04'39.16"E 12°55'05.25" Randolph West Old Hand Group: General Forum Members Points: 322 Visits: 431 Or do it the hardcore way like Peso's example :-) idrisgani Grasshopper Group: General Forum Members Points: 19 Visits: 22 Thanks for the Reply. I have already tried with converting the real into decimal before converting to VarcharDeclare @real realSet @real=Inputprint Round(Convert(varchar(30),Convert(Decimal(15,7),@real)),2)If Input = 19.005, expected Result is 19.01. but i cant able to reproduce the same. Actual result is 19i can able to achieve the result when Input = 19.0051( Result is 19.01). Jeff Moden SSC Guru Group: General Forum Members Points: 51795 Visits: 40308 idrisgani (7/2/2009)Thanks for the Reply. I have already tried with converting the real into decimal before converting to VarcharDeclare @real realSet @real=Inputprint Round(Convert(varchar(30),Convert(Decimal(15,7),@real)),2)If Input = 19.005, expected Result is 19.01. but i cant able to reproduce the same. Actual result is 19i can able to achieve the result when Input = 19.0051( Result is 19.01).Based on that reply, I'm thinking that you didn't try Peso's code which actually does work. Don't assume that just reading the code will be your answer. Try it. ;-) --Jeff ModenRBAR is pronounced ree-bar and is a Modenism for Row-By-Agonizing-Row.First step towards the paradigm shift of writing Set Based code: Stop thinking about what you want to do to a row... think, instead, of what you want to do to a column.Although they tell us that they want it real bad, our primary goal is to ensure that we dont actually give it to them that way.Although change is inevitable, change for the better is not.Just because you can do something in PowerShell, doesnt mean you should. Helpful Links:How to post code problemsHow to post performance problemsForum FAQs idrisgani Grasshopper Group: General Forum Members Points: 19 Visits: 22 Hi Peso, Thanks for the code.Your logic works well when the input type is of decimal. but my input type is real.it is rounded to 19 and not 19.01, when the input type is of real. SwePeso SSCrazy Group: General Forum Members Points: 2731 Visits: 3431 And that's the culprit. Due to the binary interpretation of REAL and FLOAT datatypes1 / 2^n + 1 / 2^(n+1) + 1 / 2^(n+2) + 1 / 2^(n+3) + ...the value may not be stored exactly as you want. So you are left with two choices1. Keep REAL and learn to live with it2. Change to decimal and get what you want, all the times. N 56°04'39.16"E 12°55'05.25" idrisgani Grasshopper Group: General Forum Members Points: 19 Visits: 22 Hi. i can able to get what i am expected when i use the below codeDeclare @real Decimal(15,7)Set @real=19.005print ROUND(@real + CAST(0.5E * POWER(0.1E, 2) AS DECIMAL(15, 3)), 2, 1)Output = 19.01i am not able to predict the length of the digit after dot, it may vary. so the length of the decimal used while casting should not be hard-coded. i cant able to supply the length at runtime like decimal(15,@n+1).Thanks,Idris Gani R SwePeso SSCrazy Group: General Forum Members Points: 2731 Visits: 3431 print cast( ROUND(@real + CAST(0.5E * POWER(0.1E, 2) AS DECIMAL(15, 3)), 2, 1) AS decimal(15, 2)) N 56°04'39.16"E 12°55'05.25"