how to change the value of one column in each row ?

i am using C# for windows application and sql server 2005.

create table employeetable(id int not null primarykey, name varchar(100), salary float);
now i have an interface which is used to insert values to this table

id name salary
101 Girmay 350
102 Gech 250
103 Mele 400
104 Rahwa 140

now i want to increase the salary of all the employee in my table by any folds...
for example if i can change it the salary two fold.. i can make a sql statment like this


select salary*2 as newsalary from employeetable. this works fine.. but it is only temporary just to display only.

now i have a textbox and a button.
i want to input any number in the textbox so that it will update each row by multiplying the current salary with the number in the textbox.
so how can i do this?

A SELECT statement is for retrieving data. If you want to update data you use an UPDATE statement, e.g.

sql Code:

UPDATE Employee SET Salary = Salary * 2

You would create a SqlCommand containing that SQL code and call its ExecuteNonQuery method. That will do all the work on the database itself, so there's no need to retrieve anything.