錯誤：MySQL - 操作數應該包含1列。

Question

這個查詢在我直接在MySQL中輸入時可以工作，但在C#中卻不行。

double deltaTime = (DateTime.Now - collectTime).TotalSeconds;


string query = String.Format("UPDATE buildings LEFT JOIN server_buildings ON buildings.global_id = server_buildings.global_id AND buildings.level = server_buildings.level SET budings. . boost >= NOW(), 2, 1)) WHERE buildings.global_id IN('generator', 'test')", deltaTime / 3600d);

只是得到了錯誤MySQL - 操作數應該包含1列。感謝建議！ :)

預計隨著時間的推移，它會在"storage"中增加值。

Answer 1

我對MySQL還比較新。這是帶有參數的查詢。

string query = String.Format("UPDATE buildings JOIN server_buildings ON buildings.global_id = server_buildings.global_id AND buildings.level = server_buildings.level SET buildings.storage = buildings.storage + (server_buildings.speed * ?Num * IF(buildings.boost >= NOW(), 2, 1)) WHERE buildings.global_id IN('generator', 'test')");
                     
            using (MySqlCommand command = new MySqlCommand(query, connection))
            {
                MySqlParameter param = new MySqlParameter("?Num", (deltaTime / 3600d));
                command.Parameters.Add(param);
      
               command.ExecuteNonQuery();
            }