查询列的确切日期C＃

Question

我使用这个代码将数据插入到一个Access数据库文件

decimal quantity; 
     if (!Decimal.TryParse(textBox9.Text, out quantity)) 
      MessageBox.Show("Invalid number"); 
     else 
     { 

      using (System.Data.OleDb.OleDbConnection conn = new System.Data.OleDb.OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0;Data source=|DataDirectory|\\crepeDB.accdb;")) 
      { 
       conn.Open(); 
       string query = @"insert into Sales (Sdate,SQuantity) 
        values (@date, @qta)"; 
       System.Data.OleDb.OleDbCommand cmd = new System.Data.OleDb.OleDbCommand(query, conn); 
       cmd.Parameters.Add("@date", OleDbType.Date).Value = dateTimePicker1.Value; 
       cmd.Parameters.Add("@qta", OleDbType.Decimal).Value = quantity; 
       cmd.ExecuteNonQuery(); 
      } 
     } 

现在，我想今天的总SQuantity期间的总和，所以我用这个代码，但它不断给我的错误

public void Calculate() 
    { 

      using (System.Data.OleDb.OleDbConnection conn = new System.Data.OleDb.OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0;Data source=|DataDirectory|\\crepeDB.accdb;")) 
     { 
       conn.Open(); 
       string query = @"select SQuantity SUM(SQuantity) AS 'Total' From Sales where Sdate = '"+ dateTimePicker1.Value +"'"; 
       System.Data.OleDb.OleDbCommand cmd = new System.Data.OleDb.OleDbCommand(query, conn); 
       cmd.ExecuteNonQuery(); 
      textBox1.Text = cmd.ExecuteScalar().ToString(); 

     } 

    } 

    private void frmShiftEnd_Load(object sender, EventArgs e) 
    { 
     Calculate(); 
    } 

Answer 1

试试这个：

string query = @"select SUM(SQuantity) AS 'Total' From Sales where Sdate = @datetime"; 
System.Data.OleDb.OleDbCommand cmd = new System.Data.OleDb.OleDbCommand(query, conn); 
cmd.Parameters.Add("@datetime", OleDbType.Date).Value = dateTimePicker1.Value; 

我删除德SQuantity和附加值为PARAM ETERS。不要直接将你的字段的值用于你的sql文本。它可能会导致你有安全事件。