Question

我希望获得与我的bundnum列相关的记录数量的SQL Count，并将其显示在我的textblock中。有什么建议吗？

SqlConnection conn = new SqlConnection("db connection");

SqlCommand comm = conn.CreateCommand();

comm.CommandText = "SELECT COUNT(*) FROM dbo.tablename WHERE bundnum = 'values' ";
conn.Open();
int returnValue = (int)comm.ExecuteScalar();
txtNumber.Text = returnValue.ToString();

Answer 1

使用Google，我发现了helpful link并经过一些修改后发现：

Int32 newCount = 0;
string newValue = "something";
string sql =
    "SELECT COUNT(*) FROM dbo.tablename WHERE bundnum = '@myValue'";
using (SqlConnection conn = new SqlConnection(connString))
{
    SqlCommand cmd = new SqlCommand(sql, conn);
    cmd.Parameters.Add("@myValue", SqlDbType.VarChar);
    cmd.Parameters["@myValue"].Value = newValue;
    try
    {
        conn.Open();
        newCount = (Int32)cmd.ExecuteScalar();
    }
    catch (Exception ex)
    {
        Console.WriteLine(ex.Message);
    }
}

SQL从数据库中的特定列计数

1 个答案: