I have a table like this:
我有这样一张桌子：
Date Sales Department Store
02/01/2012 4.09 Toys A
03/01/2012 5.90 Toys A
02/01/2012 6.64 Toys B
03/01/2012 4.71 Toys B
02/01/2012 16.72 Toys C
03/01/2012 1.37 Toys C
02/01/2012 13.22 Movies A
03/01/2012 18.06 Movies A
02/01/2012 5.97 Movies B
03/01/2012 16.71 Movies B
02/01/2012 15.38 Movies C
03/01/2012 19.75 Movies C
Date 
