sql statement if exists update else insert sql server -

nice again m working on project calculate measures , numbers , insert data inside datagridview(dgv) number.text , measure.text if value of measure.text present in dgv son update number cell new value + present value problem how so.... tried alot of sql statements have errors

private sub button3_click(sender object, e eventargs) handles button3.click          if not sqlcon.state = connectionstate.open             '  open connection             sqlcon.open()         end if                 com2 = new sqlcommand("update frames set [number] = [number] + '" & number.text & "' measure = '" & measure.text & "'", sqlcon)                 com2.executenonquery()                  com = new sqlcommand("insert frames ([number],measure) values('" & number.text & "','" & measure.text & "'),('" & number1.text & "','" & measure1.text & "')", sqlcon)                 com.executenonquery()              end if         next       end sub 

this code m working on search better way , find ones

com2 = new sqlcommand("update frames set [number] = [number] + '" & number.text & "' measure = '" & measure.text & "' if @@rowcount=0 insert frames ([number],measure) values('" & number.text & "','" & measure.text & "'),('" & number1.text & "','" & measure1.text & "'", sqlcon) com2.executenonquery() 

but give me error incorrect syntax near '93.5' .........93.5 value exists in measure.text sql statement ok except error dont know why have tried way

com = new sqlcommand("if not exists (select *  frames) begin insert frames ([number],measure) values('" & number.text & "','" & measure.text & "'),('" & number1.text & "','" & measure1.text & "') end else begin update frames set [number] = [number] + '" & number.text & "' measure = '" & measure.text & "'", sqlcon) com2 = new sqlcommand("if exists (select * frames) begin update frames set [number] = [number] + '" & number.text & "' measure = '" & measure.text & "' end else begin insert frames ([number],measure) values('" & number.text & "','" & measure.text & "'),('" & number1.text & "','" & measure1.text & "' end", sqlcon) com2.executenonquery() 

i got error "****incorrect syntax near keyword 'then'.

incorrect syntax near keyword 'else'.

incorrect syntax near keyword 'end'.****" or

i got error "incorrect syntax near '61.19'." .........61.19 value present in measure.text

please me find way without errors or wrong in these????

i heared transaction searched way , understand nothing .....