HI, In SSRS, i want to use stdev() funtions with 31 columns. how to use that. for ex: Patient admitted on each day per month. Column list: site, patient D1 D2 D3 D4.............. D31 Values c004 alex 1 2 1 0...................1 c004 bret 0 0 0 1...................3 Here i have to find the StDev value for D1 to D31 columns. How to use the Stdev() for multiple columns. Regards, Fazlu.

Hi Fazlu, By generally, Stdev() function returns the standard deviation of all non-null values of the specified expression, Syntax is below: StDev(Expression, Scope) However, your requirement is to get the Stdev value for 31 column's value, that is to say you have 31 expressions. So this requirement could not be achieved just utilizing this function. Actually Stdev() function is got from below equation Firstly, you should get the average value for these 31 column's value, average=(Fields!D1.value+Fields!D2.value+......+Fields!D31.value)/31 Then you should give a power value for (x1-average) and (X2-average).....(Xn-average), we call this value is numerator, numerator's value = Power((x1-average), 2)+Power((x2-average), 2)+.....Power((x3-average), 2) Thirdly, numerator's value should divide (n-1) , we call this value Irms, expression= numerator/(N-1) Lastly, we should calculate square root value for Irms utilizing the Sqrt function, expression =Sqrt(Irms) Thanks, Challen Fu