[英]How to store objects max(date) and min(date) from mysql query
I'm semi-new from C# and i've never store objects from mysql query. 我是C#的新手,我从不存储来自mysql查询的对象。 I've declared 2 Datetimes variables:
我已经声明了2个Datetimes变量:
DateTime date_min
DateTime date_max
I'd like to store max(date) and min(date) from below query 我想从下面的查询中存储max(date)和min(date)
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';";
like: max(date) = MAX(order_status.END_DATE)
例如:
max(date) = MAX(order_status.END_DATE)
min(date) = MIN(order_status.BEGIN_DATE)
which i want use in this loop: 我想在此循环中使用:
for (DateTime date = date_min; date <= date_max; date = date.AddDays(1))
{
string query2 = "SELECT COUNT(leave.ID_PRACOWNIKA) 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';";
}
Can someone please show what should kind of code line should I write? 有人可以告诉我应该写什么样的代码行吗? maybe cmd.Parameters is enough?
也许cmd.Parameters够了吗? THX for any help.
THX寻求任何帮助。
there is my code: 有我的代码:
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))
{
string query2 = "SELECT COUNT(leave.ID_PRACOWNIKA) 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';";
}
}
}
You can use ExecuteReader to retrieve the value as below, 您可以使用ExecuteReader检索以下值,
using (MySqlConnection connection = new MySqlConnection(connectionString))
{
using(var command = new MySqlCommand(query1, con))
{
using(var reader = command.ExecuteReader())
{
while (reader.Read())
{
date_min = Convert.ToDateTime(reader[0]);
date_max = Convert.ToDateTime(reader[1]);
}
}
}
}
Hope it helps. 希望能帮助到你。
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