Calculating difference of dates between date of invoice and date of order. List includes the values if the date difference is less than ten:

Date of invoice	Order date	Difference of dates between date of invoice and date of order
2008-07-15	2008-07-06	9
2008-09-20	2008-09-15	5
2007-08-30	2007-08-22	8
2007-09-24	2007-09-20	4