Rafael, I did not understand how you want to import this spreadsheet to Mysql, if you are using the Java language to import it you can use the Simpledateformat method (java.text.Simpledateformat Javadoc) to format your date, it is very simple and easy to be implemented:
SimpleDateFormat formatter = new SimpleDateFormat("yyyy/MM/dd");
String dateInString = "07/06/2013";
try {
Date date = formatter.parse(dateInString);
System.out.println(date);
System.out.println(formatter.format(date));
} catch (ParseException e) {
e.printStackTrace();
}
That bit of Codic will do for you. However, if you only want to give an initial load in Mysql you can use a very useful tool, PDI (Pentaho Data Integration), sofware very good and that particurlamente taste very much.
I hope I’ve helped!
Abs