VB MySQL을 AddWithValue는 값을 전달하지 않습니다 성공적으로

Question

내가 가지고있는 VB 코드

Dim cmd As New MySqlCommand("SELECT code FROM decoder WHERE ann_id = @aid", conn) 

cmd.Parameters.AddWithValue("@aid", 1) 

Dim reader As MySqlDataReader = cmd.ExecuteReader() 

reader.Read()를 내가

Dim cmd As New MySqlCommand("SELECT code FROM decoder WHERE ann_id = 1", conn) 

Dim reader As MySqlDataReader = cmd.ExecuteReader() 

하여 코드를 대체이라면 그러나, 나에게 아무것도주지 않는다 다음

reader.Read()는 올바른 결과를 제공합니다. 추가를 사용하여 시도했지만 도움이되지 않습니다. 내가 여기서 무엇을 놓치고 있니?

많은 감사,

Answer 1

제거 @

Dim cmd As New MySqlCommand("SELECT code FROM decoder WHERE ann_id = @aid", conn) 
cmd.Parameters.AddWithValue("aid", 1) 
Dim reader As MySqlDataReader = cmd.ExecuteReader() 

Answer 2

Private Sub ButtonInsert_Click(sender As Object, e As EventArgs) Handles ButtonInsert.Click 
    Dim conn As New MySqlConnection 
    Dim cmd As New MySqlCommand 

    conn.ConnectionString = Me.Tag.ToString 

    Try 
     conn.Open() 
     cmd.Connection = conn 

     cmd.CommandText = "INSERT INTO myTable VALUES(NULL, @number, @text)" 
     cmd.Prepare() 

     cmd.Parameters.AddWithValue("@number", 1) 'sets @number to be numeric 
     cmd.Parameters.AddWithValue("@text", "One") 'sets @text to be characters 

     For i = 1 To 1000 

      cmd.Parameters("@number").Value = i 
      cmd.Parameters("@text").Value = "A string value" 

      cmd.ExecuteNonQuery() 
     Next 
    Catch ex As MySqlException 
     MessageBox.Show("Error " & ex.Number & " has occurred: " & ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error) 
    End Try