Insert dates on diferent columns at second time

Hello
 
 
I have gridview and I need to insert date values depending of values. So the first date value it ill go to the fisrt column.
Then I get the second value automatic, and it go to the second column, like has I show on image.
I have a code like that, but is not correct:
 
  
conexaoMySQL = New MySqlConnection("server=localhost; user; password=root; database=teste")
 
strSQL = "INSERT INTO TABELA (date1) VALUES ('" + Date + "')
 
 
if date1 > date2 then
 
strSQL = "INSERT INTO TABELA (date2) VALUES ('" + Date + "')
 
 
 
        conexaoMySQL.Open()
        cmd.ExecuteNonQuery()
        conexa ...