Question

what is wrong with my code?

Dim x As Integer
    Dim sql As String
    ModConnectDb.OpenDatabase()
    conn.Open()
    For x = 200 To 208
        sql = "select * from ttransaction where no_room= 'x' and status= 'checkin '"
        cmd = New SqlCommand(sql, conn)
        dtReader = cmd.ExecuteReader
        If dtReader.HasRows = False Then
            cbo_numberroom.Items.Add(x)
        End If
        dtReader.Close()
    Next

I’m making an application for the hospital. VIP room has an room number 200 to 208
purpose of this code is. if radio button is selected who is a VIP, he will check whether the number 200 is already in the database and whether the status of the room checkin. if yes, then the number 200 will not appear in the combobox noRoom again.

but the results of this code. although the 200 has been filled, still appear in the combobox to select the room number
I really hope that help

Thank You Before

Answer 1

1. You’re not using parameterized queries
2. There is a space character after ‘checkin ‘, which may not be in the database, so there’s no match
3. You’re not using the room number as a parameter to the SQL query
4. Most importantly: you’re not telling us what the error is!

I can see that you’re writing no_room='x'. This checks whether there is an ‘x’ character in the column no_room of your database.

If you want to check whether the room with the number of x is already in the database, you should use

cmd = New SqlCommand("SELECT * FROM tTransaction WHERE no_room = @roomNumber AND status = 'checkin'", conn)
cmd.Parameters.AddWithValue("@roomNumber", x)
...