Group by multiple columns on a single MySql stored procedure

Yes, it is possible using a Dynamic SQL. We can create a query string, and then prepare and execute it. This will allow us to specify dynamic column name, which is not possible directly.

You will also need to use one more parameter to specify which column to use in Group By

DELIMITER $$

CREATE DEFINER=`root`@`localhost` 
  PROCEDURE `GetChartApprovedData`(in siteValue varchar(45),
                                   in skillValue varchar(100), 
                                   in shiftValue varchar(100), 
                                   in tmValue varchar(45), 
                                   in grpmValue varchar(45), 
                                   in dateValue date, 
                                   in dateValue1 date, 
                                   in groupByColumn varchar(64)) 
-- add extra in parameter, groupByColumn, to specify which column to group upon 

BEGIN

SET query_str = CONCAT('SELECT 
                          count(agentlogin) AS totalApproved, 
                          shift AS Shift, 
                          skill AS Skill, 
                          tm AS TM, 
                          grpM AS GrpM
                        FROM approved
                        WHERE (sitevalue IS NULL
                               OR site = sitevalue)
                          AND (skillvalue IS NULL
                               OR skill = skillvalue)
                          AND (shiftvalue IS NULL
                               OR shift = shiftvalue)
                          AND (tmValue IS NULL
                               OR tm = tmValue)
                          AND (grpmValue IS NULL
                               OR grpM = grpmValue)
                          AND (dateValue IS NULL
                               OR date BETWEEN dateValue AND dateValue1)
                        GROUP BY ', 
                        groupByColumn); -- concatenate the group by column param

-- prepare the query
PREPARE stmt FROM query_str;

-- execute the query
EXECUTE stmt;

-- Clear up
DEALLOCATE PREPARE stmt;

END $$

DELIMITER ;

One way around your problem would be to do both queries inside your procedure (one to GROUP BY shift, and one to GROUP BY skill, and use a flag in the results to indicate if the result was data grouped by shift or skill:

CREATE DEFINER=`root`@`localhost` PROCEDURE `GetChartApprovedData`(in siteValue varchar(45),
in skillValue varchar(100), in shiftValue varchar(100), in tmValue varchar(45), 
in grpmValue varchar(45), in dateValue date, in dateValue1 date)
BEGIN
SELECT 'skill' AS type, count(agentlogin) AS totalApproved, skill AS Skill, tm AS TM, grpM AS GrpM
   FROM approved
   WHERE (sitevalue IS NULL
           OR site = sitevalue)
         AND (skillvalue IS NULL
               OR skill = skillvalue)
         AND (shiftvalue IS NULL
               OR shift = shiftvalue)
         AND (tmValue IS NULL
                OR tm = tmValue)
         AND (grpmValue IS NULL
                OR grpM = grpmValue)
         AND (dateValue IS NULL
                OR date BETWEEN dateValue AND dateValue1)
                group by skill;
SELECT 'shift' AS type, count(agentlogin) AS totalApproved, shift AS Shift, tm AS TM, grpM AS GrpM
   FROM approved
   WHERE (sitevalue IS NULL
           OR site = sitevalue)
         AND (skillvalue IS NULL
               OR skill = skillvalue)
         AND (shiftvalue IS NULL
               OR shift = shiftvalue)
         AND (tmValue IS NULL
                OR tm = tmValue)
         AND (grpmValue IS NULL
                OR grpM = grpmValue)
         AND (dateValue IS NULL
                OR date BETWEEN dateValue AND dateValue1)
                group by shift;
END

Then in your c# code you would change these lines:

    this.Chart2.Series["Series1"].Points.AddXY(myread["Shift"], myread["totalApproved"]);
    this.Chart1.Series["Series1"].Points.AddXY(myread["Skill"], myread["totalApproved"]);

to:

if (myread["Type"] == "shift") {
     this.Chart2.Series["Series1"].Points.AddXY(myread["Shift"], myread["totalApproved"]);
}
if (myread["Type"] == "skill") {
     this.Chart1.Series["Series1"].Points.AddXY(myread["Skill"], myread["totalApproved"]);
}

If you just want to reduse c# code size than you can use the stored procedure provided by Madhu Bhaiya with the code bellow to achieve desired result:

    private void GetChartData()
    {
        string MyConString = ConfigurationManager.ConnectionStrings["connStr"].ConnectionString;
        MySqlConnection con = new MySqlConnection(MyConString);


        //PTK: TypeOfChartValue should be change with chart type you are using (I did not know what chart library you are using in your code
        Dictionary<string, TypeOfChartValue> charts = new Dictionary<string, Chart>()
        {
            { "shift", this.Chart2 },  //PTK: the first value here is a column name to use in group by , the second is the chart to fill with resulted data. this line means that the Chart2 must be filled with data grouped by  'shift'
            { "skill", this.Chart1 }  //PTK: the first value here is a column name to use in group by , the second is the chart to fill with resulted data. this line means that the Chart1 must be filled with data grouped by  'skill'
            //PTK: you can add here as many charts as you wish
        };
        foreach (string groupby in charts.Keys)
        {
            //PTK: TypeOfChartValue should be change with chart type you are using (I did not know what chart library you are using in your code
            TypeOfChartValue chart = charts[groupby];

            MySqlCommand cmd = new MySqlCommand("GetChartApprovedData");
            cmd.CommandType = CommandType.StoredProcedure;
            string siteValue = null;
            DateTime? dateValue = null;
            DateTime? dateValue1 = null;
            if (ddlSite.SelectedValue != null && ddlSite.SelectedValue != "0")
            {
                siteValue = ddlSite.SelectedValue;
            }
            if (ViewState["Date"] != null && ViewState["Date"].ToString() != "0")
            {
                dateValue = DateTime.Parse(ViewState["Date"].ToString());
            }
            if (ViewState["Date1"] != null && ViewState["Date1"].ToString() != "0")
            {
                dateValue1 = DateTime.Parse(ViewState["Date1"].ToString());
            }
            cmd.Parameters.AddWithValue("siteValue", siteValue);
            cmd.Parameters.AddWithValue("dateValue", dateValue);
            cmd.Parameters.AddWithValue("groupByColumn", groupby);

            cmd.Connection = con;
            con.Open();
            MySqlDataReader myread = cmd.ExecuteReader();
            while (myread.Read())
            {
                chart.Series["Series1"].Points.AddXY(myread["Shift"], myread["totalApproved"]);
                chart.Series["Series1"].IsValueShownAsLabel = true;
                chart.Series["Series1"].Label = "#VALY(#PERCENT)";
                chart.Series["Series1"].ToolTip = "Shift: #VALX \\nCount: #VALY";
                chart.ChartAreas["ChartArea1"].AxisX.LabelStyle.Interval = 1;
                chart.Legends.Clear();
                chart.ChartAreas["ChartArea1"].AxisX.MajorGrid.Enabled = false;
                chart.ChartAreas["ChartArea1"].AxisY.MajorGrid.Enabled = false;
                chart.Series["Series1"].Color = Color.DarkOrange;

            }
            con.Close();
        }
    }