How to define mysql parameters min(date) and max(date)

Hi everyone.

I'm semi-new from C# and i've never store objects from mysql query. In this case i've declared 2 Datetimes variables:

DateTime date_min
DateTime date_max

I'd like to define mysql Parameters max(date) and min(date) before the lopp from below query:

string query1 = "SELECT MIN(order_status.BEGIN_DATE) AS 'BEGIN DATE', MAX(order_status.END_DATE) AS 'END DATE' FROM project1.order_status INNER JOIN project1.orders ON orders.ID_ORDER = order_status.ID_ORDER WHERE orders.NUMBER_ORDER = 'TEST';";

I'd try like this for example:

SqlParameter param = new SqlParameter();
param.ParameterName = "@max_date";
param.Value = input_max_date;

Then i want to use like this:

string query1 = "SELECT @min_date AS 'BEGIN DATE', @max_date AS 'END DATE' FROM project1.order_status INNER JOIN project1.orders ON orders.ID_ORDER = order_status.ID_ORDER WHERE orders.NUMBER_ORDER = 'TEST';";

because of :

@min_date = MIN(order_status.BEGIN_DATE)
@max_date = MAX(order_status.END_DATE)

then i have the loop:

for (DateTime date = date_min; date <= date_max; date = date.AddDays(1))
{
var cmd = new MySqlCommand(query1, connection);
string query2 = "SELECT COUNT(leave.ID_WORKER) AS 'NUMBER OF WORKERS ON LEAVE' FROM project1.leave WHERE DATE(leave.BEGIN_DATE) <= '"+date+"' AND DATE(leave.END_DATE) >= '"+date+"';";
string query3 = "SELECT TIME_FORMAT(SEC_TO_TIME(SUM(TIME_TO_SEC(order_status.END_DATE) - TIME_TO_SEC(order_status.BEGIN_DATE))), '%H:%i:%s') AS 'TIME OF ALL ORDERS IN DAY' FROM project1.order_status INNER JOIN project1.orders ON orders.ID_ORDER = order_status.ID_ORDER WHERE (DATE(order_status.BEGIN_DATE) = '"+date+"' AND DATE(order_status.END_DATE) = '"+date+"');";
string query4 = "SELECT TIME_FORMAT(SEC_TO_TIME(SUM(TIME_TO_SEC(order_status.END_DATE) - TIME_TO_SEC(order_status.BEGIN_DATE))), '%H:%i:%s') AS 'TIME OF ORDER IN DAY' FROM project1.order_status INNER JOIN project1.orders ON orders.ID_ORDER = order_status.ID_ORDER WHERE (DATE(order_status.BEGIN_DATE) = '"+date+"' AND DATE(order_status.END_DATE) = '"+date+"') AND orders.NUMBER_ORDER = 'TEST';";
using (var command = new MySqlCommand(query1, connection))
{
using (var reader1 = command.ExecuteReader())
{
while (reader1.Read())
{
date_min = Convert.ToDateTime(reader1[0]);
date_max = Convert.ToDateTime(reader1[1]);
}
}
}
var cmd1 = new MySqlCommand(query2, connection);
var cmd2 = new MySqlCommand(query3, connection);
var cmd3 = new MySqlCommand(query4, connection);
}

Can someone please show what should kind of code lines should I write? maybe cmd.Parameters is enough? THX for any help.

There is my code:

public partial class GenerateChartsOfOrders : Form
{
DateTime date_min;
DateTime date_max;
public GenerateChartsOfOrders()
{
InitializeComponent();
}
public void loaddata2()
{
string query1 = "SELECT MIN(order_status.BEGIN_DATE) AS 'BEGIN DATE', MAX(order_status.END_DATE) AS 'END DATE' FROM project1.order_status INNER JOIN project1.orders ON orders.ID_ORDER = order_status.ID_ORDER WHERE orders.NUMBER_ORDER = 'TEST';";
for (DateTime date = date_min; date <= date_max; date = date.AddDays(1))
{
var cmd = new MySqlCommand(query1, connection);
string query2 = "SELECT COUNT(leave.ID_WORKER) AS 'NUMBER OF WORKERS ON LEAVE' FROM project1.leave WHERE DATE(leave.BEGIN_DATE) <= '"+date+"' AND DATE(leave.END_DATE) >= '"+date+"';";
string query3 = "SELECT TIME_FORMAT(SEC_TO_TIME(SUM(TIME_TO_SEC(order_status.END_DATE) - TIME_TO_SEC(order_status.BEGIN_DATE))), '%H:%i:%s') AS 'TIME OF ALL ORDERS IN DAY' FROM project1.order_status INNER JOIN project1.orders ON orders.ID_ORDER = order_status.ID_ORDER WHERE (DATE(order_status.BEGIN_DATE) = '"+date+"' AND DATE(order_status.END_DATE) = '"+date+"');";
string query4 = "SELECT TIME_FORMAT(SEC_TO_TIME(SUM(TIME_TO_SEC(order_status.END_DATE) - TIME_TO_SEC(order_status.BEGIN_DATE))), '%H:%i:%s') AS 'TIME OF ORDER IN DAY' FROM project1.order_status INNER JOIN project1.orders ON orders.ID_ORDER = order_status.ID_ORDER WHERE (DATE(order_status.BEGIN_DATE) = '"+date+"' AND DATE(order_status.END_DATE) = '"+date+"') AND orders.NUMBER_ORDER = 'TEST';";
using (var command = new MySqlCommand(query1, connection))
{
using (var reader1 = command.ExecuteReader())
{
while (reader1.Read())
{
date_min = Convert.ToDateTime(reader1[0]);
date_max = Convert.ToDateTime(reader1[1]);
}
}
}
var cmd1 = new MySqlCommand(query2, connection);
var cmd2 = new MySqlCommand(query3, connection);
var cmd3 = new MySqlCommand(query4, connection);
}
}
}