c# - 如何传递mysql查询和连接字符串并获取结果？

Question

我有一个像这样的 SQL 连接字符串:

Data Source=myServerAddress;Initial Catalog=myDataBase;User Id=myUsername;Password=myPassword;

我有一个这样的查询:stratdate = 10-03-2001，Enddate = 20-08-2008

string sql =  string.Format(@"SELECT CONCAT(UPPER(SUBSTRING(visit_Status, 1, 1)), SUBSTRING(visit_Status FROM 2))  as Status, COUNT('x') AS Visits
                              FROM visits
                              WHERE visit_Date BETWEEN '{0}' AND '{1}'
                              GROUP BY visit_Status", StartDate.ToString(dateFormat), EndDate.ToString(dateFormat)) 

我不知道如何使用连接字符串将此查询传递到数据库并将结果放入数据表中。我正在使用 C# 编写 WinForms 应用程序并使用 MySQL 作为数据库。

我该怎么做？有人对此有任何想法吗？我如何将其作为命令文本传递给 MySQL？有人可以帮我提供示例代码片段吗？

Answer 1

public DataTable GetVisits(System.DateTime startDate, System.DateTime endData)
{
    const string SQL = "SELECT CONCAT(UPPER(SUBSTRING(visit_Status, 1, 1)), SUBSTRING(visit_Status FROM 2))  as Status, COUNT('x') AS Visits FROM(visits)  WHERE visit_Date BETWEEN @startDate AND @endData GROUP BY visit_Status";
    const string CONNSTR = "Data Source=myServerAddress;Initial Catalog=myDataBase;User Id=myUsername;Password=myPassword;";
    var tblVisits = new DataTable("Visits");
    using (var conn = new MySql.Data.MySqlClient.MySqlConnection(CONNSTR)) {
        var cmd = new MySql.Data.MySqlClient.MySqlCommand(SQL, conn);
        var da = new MySql.Data.MySqlClient.MySqlDataAdapter(cmd);
        var param = new MySql.Data.MySqlClient.MySqlParameter("@startDate", MySql.Data.MySqlClient.MySqlDbType.Date);
        param.Direction = ParameterDirection.Input;
        param.Value = startDate;
        cmd.Parameters.Add(param);
        param = new MySql.Data.MySqlClient.MySqlParameter("@endDate", MySql.Data.MySqlClient.MySqlDbType.Date);
        param.Direction = ParameterDirection.Input;
        param.Value = endData;
        cmd.Parameters.Add(param);
        conn.Open();
        da.Fill(tblVisits);
    }

    return tblVisits;
}