retreive data via checkbox

Hi expert,
I have created two checkboxes and if one of them is checked, the data will be retrieved. Currently my problem is if the first checkbox (e.g. pricing<10)  is checked, all of the data (pricing >20) are retrieved and it is the same with the second checkbox( all of  the data are displayed).  I really need your advice and I am very appreciated!
Below are the code:

 Sub Check_Clicked(sender As Object, e As System.EventArgs)       If not page.Ispostback then If checkbox1.Checked = true then Dim strSQL strSQL = "SELECT * FROM pricing where pricing <10" call openDB()                                              Dim DBAdapter As OdbcDataAd ...