Conversion failed when converting the varchar value '@a' to data type int

Question

I'm trying to update a column in SQL but I get this Error..

Code:

SqlConnection cn = new SqlConnection("CONNECTION STRING");
            SqlCommand com = new SqlCommand("update details set Available='Yes' where License='@a'", cn);
            com.Parameters.AddWithValue("@a", num);
            cn.Open();
            com.ExecuteNonQuery();
            cn.Close();

Answer 1

Remove the single quotes from around the @a

SqlConnection cn = new SqlConnection("CONNECTION STRING");
            SqlCommand com = new SqlCommand("update details set Available='Yes' where License=@a", cn);
            com.Parameters.AddWithValue("@a", num);
            cn.Open();
            com.ExecuteNonQuery();
            cn.Close();