關於數據庫選擇查詢困惑

Question

我正在關注一個會話教程。問題是這部分。

OleDbCommand fecth = new OleDbCommand(
    "SELECT * FROM YONETICI Where YNAME'" + 
     txtad.Text + "' and YPASS'" + txtpass.Text + "' ", 
    con); 

在這部分我得到一個異常命名語法不正確-Missing運營商（我曾嘗試翻譯）

這是代碼

OleDbConnection con = new OleDbConnection(
     "Provider=Microsoft.ACE.OLEDB.12.0;Data Source="+ 
     Server.MapPath("App_Data\\db.accdb")); 
    con.Open(); 



    OleDbCommand fecth = new OleDbCommand(
      "SELECT * FROM YONETICI Where YNAME'" + 
      txtad.Text + "' and YPASS'" + txtpass.Text + "' ", 
      con); 
    OleDbDataReader dr=fecth.ExecuteReader(); 
    if(dr.Read()){ 
    Session.Add("value",txtad.Text); 
    Response.Redirect("Default.aspx"); 

Answer 1

其餘的你需要一個等於運算符。

OleDbCommand fecth = new OleDbCommand(
          "SELECT * FROM YONETICI Where YNAME = '" + 
          txtad.Text + 
          "' and YPASS = '" + 
          txtpass.Text + "' ", 
          con); 

試試看。我在查詢中添加了兩個等於運算符。

Answer 2

準確，你需要添加2等號，但我喜歡寫查詢以更好的方式 ，這一次將取代下面

fetch.Parameters.addWithValue() 

與像碼值@Parameter

OleDbConnection con = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source="+Server.MapPath("App_Data\\db.accdb")); 
con.Open(); 

OleDbCommand fecth = new OleDbCommand("SELECT * FROM YONETICI Where YNAME='@txtad' and YPASS='@txtpass'", con); 

fecth.Parameters.AddWithValue("@txtad",txtad.Text); 
fecth.Parameters.AddWithValue("@txtpass",txtpass.Text); 
OleDbDataReader dr=fecth.ExecuteReader(); 
if(dr.Read()){ 
Session.Add("value",txtad.Text); 
Response.Redirect("Default.aspx");