sql - Vb.net rounding inconcistancy -

this question has answer here:

• real vs. floating point vs. money 4 answers

i using vb.net summarize information in datatable using following code.

for reason rounding works on value apart 1.

code:

private sub button4_click(sender object, e eventargs) handles button4.click     if textbox1.text = ""         'do nothing     else          dim conn new sqlclient.sqlconnection         conn             .connectionstring = "server=inlt01\sqlexpress; database=orbisbilling; integrated security=yes"             .open()         end          dim cmd new sqlclient.sqlcommand         cmd             .commandtext = "select [account], [customer lookup],round (sum ([chargedamount]),2) [sum of buy price],round (sum ([sell price]),2) [sum of sell price],[tariff lookup] [orbisbilling].[dbo].[" + textbox1.text + "] group [account], [customer lookup],[tariff lookup] order [customer lookup]"             .commandtype = commandtype.text             .commandtimeout = 30             .connection = conn         end         dim dt new datatable         dt.load(cmd.executereader)          orbisviewbillform.datagridview1             .autogeneratecolumns = true             .datasource = dt         end          cmd.dispose()         cmd = nothing         conn.dispose()         conn = nothing           orbisviewbillform.show()      end if end sub 

as can see round sum 'sell price' 2 decimal places.

here result.

56.1 1.5899999999999999 133.64 12.67 14.93 0.76 0.57 4.25 2.24 0.06 7.75 4.31 7.96 0.78 0.01 33.55 

if rounding 2, why 1.5899999999999999?

to troubleshoot changed rounding 3 , following inconstancies.

56.1 1.5899999999999999 133.643 12.671 14.928 0.764 0.568 4.253 2.2439999999999998 0.058 7.745 4.306 7.9559999999999995 0.779 0.005 33.554 

any appreciated.

thanks,

the sql server float , real data types don't store decimal values exactly.

you should consider changing database columns decimal or numeric.