how to show the draws in count using mysql? - mysql

Question

I am making a voting system in visual basic, I'm struggling to write the right query for identifying the max vote count and also showing the the same vote count, what I mean is the draw in the candidates, how can I identify if there are draws in the election... here is my code
Private Sub president()
Dim cmd1 As New MySqlCommand("SELECT MAX(VOTECOUNT) as MV FROM candidates WHERE POSITION = 'PRESIDENT'", con)
Dim rd1 As MySqlDataReader
con.Open()
rd1 = cmd1.ExecuteReader()
If rd1.Read() Then
MV = rd1("MV").ToString
End If
con.Close()
rd1.Dispose()
Dim cmd As New MySqlCommand("SELECT CONCAT(FIRSTNAME,' ',MIDDLENAME,' ',LASTNAME) AS FULLNAME,POSITION, VOTECOUNT FROM candidates WHERE POSITION = 'PRESIDENT' AND VOTECOUNT = '" & MV & "'", con)
Dim rd As MySqlDataReader
con.Open()
rd = cmd.ExecuteReader()
While rd.Read()
TextBox1.Text = (rd("FULLNAME"))
End While
rd.Close()
con.Close()

Answer 1

Using...End Using blocks ensure that your database objects are closed and disposed. You can use .ExecuteScalar to get a single value from the database. This returns an Object so a CInt is needed. I think one of your problems was that you were surrounding MV in single quotes in the second Select statement. I am sure that this is an Integer and you were passing it as a string. Using parameters solves this problem.
Private Sub president()
Using con As New MySqlConnection(ConStr),
cmd1 As New MySqlCommand("SELECT MAX(VOTECOUNT) as MV FROM candidates WHERE POSITION = 'PRESIDENT'", con)
con.Open()
Dim MV = CInt(cmd1.ExecuteScalar())
cmd1.CommandText = "SELECT CONCAT(FIRSTNAME,' ',MIDDLENAME,' ',LASTNAME) AS FULLNAME,POSITION, VOTECOUNT FROM candidates WHERE POSITION = 'PRESIDENT' AND VOTECOUNT = #MV"
cmd1.Parameters.Add("#MV", MySqlDbType.Int32).Value = MV
Using rd = cmd1.ExecuteReader()
While rd.Read()
TextBox1.AppendText(rd("FULLNAME").ToString & vbCrLf)
End While
End Using
End Using
End Sub