Data type mismatch in criteria expression. whats wrong?

how do I put an int variable in sql?

int x = Convert.ToInt32(Session["id"]);
     string MySQL = @"UPDATE users SET 
     email = '"+Request.Form["email"]+"', pname = 
'"+Request.Form["pname"]+"', accountname= 
'"+Request.Form["accountname"]+"', pid = '"+Request.Form["pid"]+"', age = 
'"+Request.Form["age"]+"',passw = '"+Request.Form["passw"]+"' where 
id='x';";

Answer

Please don’t use concatenated values in your SQL command. You are exposing your application to SQL Injection Attacks. Read more here.

Use SqlParameters instead. It is the proper way to do and safer when you are running sql commands against your database from your application.

If a value is int covert it to integer:

command.Parameters.AddWithValue("@id", int.Parse(Request.Form["id"]));

Here is a example of how to use parameters.

string mySql = @"UPDATE users SET email = @email, pname = @pname, accountname = @accountname, pid = @pid, age = @age, passw = @passw where id = @id;";

string connectionString = "Server=localhost\SQLEXPRESS;Database=[your database];User Id=sa;Password=[your password];";

using (SqlConnection connection = new SqlConnection(connectionString))
{
   SqlCommand command = new SqlCommand(mySql, connection);

   command.Parameters.AddWithValue("@email", Request.Form["email"]);
   command.Parameters.AddWithValue("@pname", Request.Form["pname"]);
   command.Parameters.AddWithValue("@accountname", Request.Form["accountname"]);
   command.Parameters.AddWithValue("@pid", Request.Form["pid"]);
   command.Parameters.AddWithValue("@age", int.Parse(Request.Form["age"]));
   command.Parameters.AddWithValue("@passw", Request.Form["passw"]);
   command.Parameters.AddWithValue("@id", int.Parse(Request.Form["id"]));

   connection.Open();
   command.ExecuteNonQuery();

}

More about SqlCommand here.