[英]No errors or results when executing simple query on SQL Server database
这是我使用SQL Server的第一种方法。 我已经将Access DB导出到SQL Server,并想在我的应用程序中使用它。 我已经将新的SQL DB添加到我的C#项目中,并用Sql
替换了OleDB
。 我现在无法执行在Access中与本地数据库完美配合的查询。
查询:
string query = @"SELECT SessionID, SemesterA, SemesterB, RoomID, SessionDate, SessionTimeStart, SessionTimeEnd" +
" FROM [Session] " +
" WHERE RoomID = @RoomID " +
" AND SessionDate = getdate() ";
我已按照VS错误的指示,用getdate()
替换了Date()
,但查询未产生任何结果(应该返回一条记录,Access DB会返回)
我的RoomSelect表单代码:
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Data.SqlClient;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
namespace AutoReg
{
public partial class RoomSelect : Form
{
DataTable queryResult = new DataTable();
public string RoomID;
RoomActiveSession RoomActiveSessionForm = new RoomActiveSession();
public RoomSelect()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
switch (listBox1.SelectedItem.ToString())
{
case "MB0302":
RoomID = listBox1.SelectedItem.ToString();
roomQuery();
break;
case "MC1001":
RoomID = listBox1.SelectedItem.ToString();
roomQuery();
break;
case "MC3203":
RoomID = listBox1.SelectedItem.ToString();
roomQuery();
break;
case "MC3204":
RoomID = listBox1.SelectedItem.ToString();
roomQuery();
break;
}
}
public void roomQuery()
{
string ConnStr = "Data Source=DUZY;Initial Catalog=AutoRegSQL;Integrated Security=True";
SqlConnection MyConn = new SqlConnection(ConnStr);
MyConn.Open();
//SQL query that todays sessions for the given roomID
string query = @"SELECT SessionID, SemesterA, SemesterB, RoomID, SessionDate, SessionTimeStart, SessionTimeEnd" +
" FROM [Session] " +
" WHERE RoomID = @RoomID " +
" AND SessionDate = getdate() ";
SqlCommand command = new SqlCommand(query, MyConn);
command.Parameters.Add("RoomID", SqlDbType.Char).Value = RoomID;
SqlDataAdapter adapter = new SqlDataAdapter(command);
adapter.Fill(queryResult);
if (queryResult.Rows.Count == 0)
{
MessageBox.Show("No active sessions today for the given room number");
MyConn.Close();
}
else
{
RoomActiveSessionForm.SetDataSouce(queryResult);
this.Hide();
RoomActiveSessionForm.ShowDialog();
MyConn.Close();
}
}
}
}
当我运行该程序时,我收到一条消息“给定房间号今天没有活动的会话”,如果查询没有结果,则应执行该消息,但事实上,我知道它应该返回一个记录)
函数getdate()
实际上返回一个datetime
。 尝试将其转换为日期:
AND SessionDate = cast(getdate() as date)
时间部分可能是问题所在–阻止了日期和日期时间之间的匹配。
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