Question

我有两张桌子

tbl_a

extension UIView {
  public class func instantiateViewFromNib<T>(_ nibName: String, inBundle bundle: Bundle = Bundle.main) -> T? {
    if let objects = bundle.loadNibNamed(nibName, owner: nil) {
      for object in objects {
        if let object = object as? T {
          return object
        }
      }
    }

    return nil
  }
}

tbl_b

VBID   |   KBID   |   SEQ
 4     |    5     |    1
 4     |    6     |    2
 5     |    6     |    1
 5     |    8     |    2

到目前为止我得到的是

VBID   |    more columns to be used
 4     |        bar
 5     |        foo

我得到的结果是

SELECT 
   tbl_b.VBID, 
   tbl_a_a.KBID, 
   tbl_a_b.KBID
FROM (tbl_b 
       INNER JOIN tbl_a AS tbl_a_a ON tbl_b.VBID = tbl_a_a.VBID) 
       INNER JOIN tbl_a AS tbl_a_b ON tbl_b.VBID = tbl_a_b.VBID 
WHERE tbl_a_a.KBID <> tbl_a_b.KBID;

我不需要第二行（或第一行），因为它代表相同的数据，我必须在查询中更改为仅接收1行更复杂的是我使用的是ACCESS

Answer 1

如果你想要哪一个并不重要：

protected void Button1_Click(object sender, EventArgs e)
    {
        string username1 = uniloginTextBox.Text;
        string password1 = passwordTextBox.Text;

        using (PrincipalContext pc = new PrincipalContext(ContextType.Domain, "cv.local"))
        {
            // validate the credentials
            bool isValid = pc.ValidateCredentials(username1, password1, ContextOptions.Negotiate);
        }

        if (IsValid == true)
        {
            Label.Text = "approved";
        }
        else if (IsValid == false)
        {
            Label.Text = "Denied";
        }

Answer 2

添加一个条件

SELECT 
   tbl_b.VBID, 
   tbl_a_a.KBID, 
   tbl_a_b.KBID
FROM (tbl_b 
       INNER JOIN tbl_a AS tbl_a_a ON tbl_b.VBID = tbl_a_a.VBID) 
       INNER JOIN tbl_a AS tbl_a_b ON tbl_b.VBID = tbl_a_b.VBID 
WHERE tbl_a_a.KBID < tbl_a_b.KBID;

Answer 3

将您的WHERE条款更改为：

WHERE tbl_a_a.KBID < tbl_a_b.KBID;

sql连接两个表，没有重复的结果

3 个答案: