Question

第一次在这里请求你的帮助。

我知道我的头衔错了，如果我们知道问题是什么，我会改变它，此刻我有点失落。

好吧，我们先去，我想从我的数据库中选择当前用户范围内的所有用户。

如果我执行查询，它会从PHPMyAdmin返回4行，哦，我应该提到我使用MariaDB

以下是查询：

SET @orig_lat=45.820904;
SET @orig_lon=-73.760549;
SET @dist=1000 * 5;//5 KM
SET @accountId=9;

SELECT SQL_CALC_FOUND_ROWS *, (((acos(sin((@orig_lat*pi()/180)) * sin((account.latitude*pi()/180))+cos((@orig_lat*pi()/180))*cos((account.latitude*pi()/180))*cos(((@orig_lon-account.longitude)*pi()/180))))*180/pi())*60*1.1515*1609.344) AS distance FROM accounts AS account HAVING distance <= @dist AND account.id <> @accountId  ORDER BY distance ASC LIMIT 50 OFFSET 0;0

现在从C＃开始，看看它是什么样的：

public static Dictionary<List<AccountData>, int> SearchAccounts(string accountId, double latitude, double longitude, int rangeInKM, int limit, int page = 1){
List<AccountData> returnList = new List<AccountData>();
int total_count = 0;
query = "SELECT SQL_CALC_FOUND_ROWS *, (((acos(sin((@orig_lat*pi()/180)) * sin((account.latitude*pi()/180))+cos((@orig_lat*pi()/180))*cos((account.latitude*pi()/180))*cos(((@orig_lon-account.longitude)*pi()/180))))*180/pi())*60*1.1515*1609.344) AS distance FROM accounts AS account HAVING distance <= @dist AND account.id <> @accountId ORDER BY distance ASC LIMIT @limit OFFSET @page;";
var rows = Database.ExecuteQuery(query,
                new QueryParameter("accountId", accountId),
                new QueryParameter("orig_lat", latitude),
                new QueryParameter("orig_lon", latitude),
                new QueryParameter("dist", 1000 * rangeInKM),
                new QueryParameter("limit", limit),
                new QueryParameter("page", page - 1));

ExecuteQuery功能代码：

public override DatabaseRow[] ExecuteQuery (string query, params QueryParameter[] parameters)
    {
        try
        {
            using (MySqlConnection connection = new MySqlConnection (connectionString))
            {
                using (MySqlCommand command = new MySqlCommand (query, connection))
                {
                    foreach (QueryParameter parameter in parameters)
                        command.Parameters.AddWithValue(parameter.name, parameter.obj);

                    connection.Open();
                    using (MySqlDataReader reader = command.ExecuteReader())
                    {
                        int fieldCount = reader.FieldCount;
                        List<DatabaseRow> rows = new List<DatabaseRow> ();

                        while (reader.Read())
                        {
                            //For each row create a DatabaseRow
                            DatabaseRow row = new DatabaseRow();

                            //And add each field to it
                            for (int i = 0; i < fieldCount; i++)
                            {
                                row.Add(
                                    reader.GetName(i),
                                    reader.GetValue(i)
                                );
                            }

                            //Add it to the rows
                            rows.Add(row);
                        }

                        return rows.ToArray();
                    }
                }
            }
        }
        catch(MySqlException e)
        {
            throw new DatabaseException(e.Message, e);
        }
    }

请注意循环while（reader.read（））...永远不会被“触发”，就像它们没有与查询匹配的行一样。

现在我有点失去了我应该做些什么来解决这个问题，欢迎大家帮忙！

非常感谢您的帮助：）

Answer 1

好吧我知道我的问题是什么，我将纬度解析为查询参数中的经度。

我离开它以防有人需要代码。始终仔细检查您的参数;）

需要改变

var rows = Database.ExecuteQuery(query,
            new QueryParameter("accountId", accountId),
            new QueryParameter("orig_lat", latitude),
            new QueryParameter("orig_lon", latitude),
            new QueryParameter("dist", 1000 * rangeInKM),
            new QueryParameter("limit", limit),
            new QueryParameter("page", page - 1));

要

var rows = Database.ExecuteQuery(query,
            new QueryParameter("accountId", accountId),
            new QueryParameter("orig_lat", latitude),
            new QueryParameter("orig_lon", longitude),
            new QueryParameter("dist", 1000 * rangeInKM),
            new QueryParameter("limit", limit),
            new QueryParameter("page", page - 1));

MySqlDataReader不读取我的查询，好像没有返回任何行，但PHPMyAdmin返回具有相同查询的行

1 个答案: