在插入期間增加一個int

Question

我想在插入期間從c＃.net頁面的MS Access表中增加一個整數。

嘗試以下操作時出現語法錯誤。還不確定我是否應該使用ExecuteNonQuery()？

OleDbCommand cmd = new OleDbCommand("INSERT INTO tblTarget(target,ref) VALUES(@target,(SELECT MAX(ref)+1 FROM tblTarget)", conn); 

cmd.Parameters.AddWithValue("@target", TextTitle.Text); 
conn.Open(); 
cmd.ExecuteNonQuery(); 
conn.Close(); 

Answer 1

正確的方式來實現你的目標是

string sql = "INSERT INTO tblTarget (target,ref) " + 
      "SELECT ?, MAX(ref)+1 FROM tblTarget"; 
OleDbCommand cmd = new OleDbCommand(sql, conn); 
cmd.Parameters.AddWithValue("@target", TextTitle.Text); 
cmd.ExecuteNonQuery(); 

Answer 2

您tblTarget後錯過支架：

OleDbCommand cmd = 
    new OleDbCommand("INSERT INTO tblTarget(target,ref) VALUES(@target,(SELECT MAX(ref)+1 FROM tblTarget))", conn); 

這裏是你的代碼的一點檢討，請嘗試使用using模式：

using(var conn = new Connection()) 
{ 
    conn.Open(); 
    string sql = "INSERT INTO tblTarget(target,ref) VALUES(@target,(SELECT MAX(ref)+1 FROM tblTarget))"; 
    OleDbCommand cmd = new OleDbCommand(sql, conn); 

    cmd.Parameters.AddWithValue("@target", TextTitle.Text); 

    cmd.ExecuteNonQuery(); 
} 

Answer 3

你缺少一個支架，請嘗試：

INSERT INTO tblTarget(target,ref) VALUES(@target,(SELECT MAX(ref)+1 FROM tblTarget)) 

但我認爲你將有其他問題，你需要的東西更接近這個：

INSERT INTO tblTarget (target, ref) 
SELECT @target AS Targ, First((SELECT MAX(ref)+1 FROM tblTarget)) AS MaxRef 
FROM tblTarget 
GROUP BY @target; 

Answer 4

我不會被SQL或代碼做增量，我們可以使用自動AutoNumber數據類型增加值訪問。

string sql = "INSERT INTO tblTarget(target) VALUES(@target)"; 
using(var conn = new Connection()) 
using(OleDbCommand cmd = new OleDbCommand(sql, conn)) 
{ 
    conn.Open(); 
    cmd.Parameters.AddWithValue("@target", TextTitle.Text); 
    cmd.ExecuteNonQuery(); 
}