INSERT vs. UPDATE [重复]

您可以在SQL中使用Exists函数。例如

SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["chestionar"].ConnectionString);       SqlCommand cmd = new SqlCommand("if Exists(Select 1 from Raspunsuri where <your unique criteria>)rn" +"Update Raspunsuri set <values you want to set> where <your unique criteriarn" +"elsern" +"INSERT INTO Raspunsuri Values(@raspuns,@cnp,@data,'1',@ip,@idsesiune)", con);    cmd.Parameters.AddWithValue("@cnp", Session["sesiune_cnp"]);       cmd.Parameters.AddWithValue("@raspuns", textbox1.Text);       cmd.Parameters.AddWithValue("@data", DateTime.Now.ToLocalTime());       cmd.Parameters.AddWithValue("@ip",ip);       cmd.Parameters.AddWithValue("@idsesiune", id_sesiune);

这应该够了吧