在select语句中使用mysql中的日期时间选择器

Question

我有两个日期时间选择器，我从那些日期时间选择器中选择范围以从表中检索信息但是我得到错误，因为它计算所有图像并给我单日期而非日期计数。

MySqlDataAdapter sda = new MySqlDataAdapter(String.Format(
      "SELECT   datetime ," +
      "sum(CASE action when '2' then 1 else 0 end) as AcceptedIMG, " +
      "sum(CASE action when '3' then 1 else 0 end) as RejectedIMG, " +
      "sum(CASE action when '4' then 1 else 0 end) as ChangeIMG " +
      "FROM customer_1.audit_trail " +
      //"GROUP BY (dateonly)" +
     // "ORDER BY  (dateonly) asc  " +
      "where datetime BETWEEN '{0}' and '{1}'",
      start.Value.ToString("yyyy/MM/dd"), 
      end.Value.ToString("yyyy/MM/dd"),
      "GROUP BY (datetime)" ), conn);
                sda.Fill(db);

                dataGridView1.DataSource = db;