Public cn As ADODB.connection
Public rs As ADODB.Recordset
Public cmd As String

'соединение с БД
Sub connection1()
cmd = "Driver={MySQL ODBC 3.51 Driver};Server=" & Dialog.txtServer & ";Port=" & Dialog.txtPort & ";Database=mydb;User=" & Dialog.txtUser & "; Password=" & Dialog.txtPasw & ";Option=3;"
Set cn = New ADODB.connection
cn.ConnectionString = cmd
cn.Open
End Sub

Private Sub Form_Load()
Dim sql, sl As String

modul1.connection1 'подключаем наш модуль

sl = "select post_id,post_name from post  ORDER BY post_id" 'sql запрос на вывод таблицы post
Set rs = New ADODB.Recordset
cn.CursorLocation = adUseClient
rs.Open sl, cn, adOpenStatic
Set DataGrid2.DataSource = rs
    DataGrid2.ReBind
    
'Text1.Text = "1"
Set Text1.DataSource = rs       ' выводим в text1.text значение столбца "post_id" из таблицы post
    Text1.DataField = "post_id"
      
    
sql = "select * from staff where post_id= " & Text1.Text & "" 'В зависимости от значения поля text1.text
                                                              'в datagrid1 выведутся значения которые соответсвуют полю text1.text
Set rs = New ADODB.Recordset
cn.CursorLocation = adUseClient
rs.Open sql, cn, adOpenStatic
Set DataGrid1.DataSource = rs
    DataGrid1.ReBind
End Sub