Create autonumber column ordered by sales date grouped by username

[#1]

Hello,

I have sales table that have usernames and sales_dates. I want to give sales number
for every sales ordered by date for every user. Then I would like to create a column
that shows the days between sales.
Black columns are original data. I would like to produce red data. How can I do that in qlikview?

Username	Sales_date	Sales_no	Date_difference
john	14.01.2013	1
john	17.01.2012	2	3
john	25.01.2013	3	8
Wade	10.01.2013	1
Wade	18.01.2013	2	8
Wade	31.01.2013	3	13

FUID	Sales_date	Sales_no	Date_diffreence
John	15.01.2012	1
John	17.01.2012	2	2
John	23.01.2012	3	6
Wade	16.01.2012	1
Wade	25.02.2012	2	40
Wade	03.03.2012	3	7
Fred	04.04.2012	1
Fred	09.04.2012	2	5
Fred	24.04.2012	3	15

FUID	Sales_date	Sales_no	Date_diffreence
John	15.01.2012	1
John	17.01.2012	2	2
John	23.01.2012	3	6
Wade	16.01.2012	1
Wade	25.02.2012	2	40
Wade	03.03.2012	3	7
Fred	04.04.2012	1
Fred	09.04.2012	2	5
Fred	24.04.2012	3	15

FUID	Sales_date	Sales_no	Date_diffreence
John	15.01.2012	1
John	17.01.2012	2	2
John	23.01.2012	3	6
Wade	16.01.2012	1
Wade	25.02.2012	2	40
Wade	03.03.2012	3	7
Fred	04.04.2012	1
Fred	09.04.2012	2	5
Fred	24.04.2012	3	15

FUID
Sales_date
Sales_no
Date_diffreence


John
15.01.2012
1



John
17.01.2012
2
2


John
23.01.2012
3
6


Wade
16.01.2012
1



Wade
25.02.2012
2
40


Wade
03.03.2012
3
7


Fred
04.04.2012
1



Fred
09.04.2012
2
5


Fred
24.04.2012
3
15

[#2]

is Your data set ordered by date?

try like this:

LOAD Username,

     Sales_date,

     if (recno()=1,1,if(Previous(Username)=Username,Previous(Sales_no)+1,1)) as Sales_no,

     if(Previous(Username)=Username, Sales_date-Previous(Sales_date),'') as Date_difference

FROM

(ooxml, embedded labels, table is Data_sample);

[#3]

Thanks.

My  dataset was not ordered. I have ordered it by username,date. But it gives error. Becuse, there is no column called sales_no . If I comment sales_no, Date_difference works fine.

Field not found - <Sales_no>

LOAD username,

     sales_date,

     if (recno()=1,1,if(Previous(username)=username,Previous(Sales_no)+1,1)) as Sales_no,

     if(Previous(username)=username, sales_date-Previous(sales_date),'') as Date_difference

FROM

[DATA.QVD](qvd)