sum selected and some unselected

[#1]

Hi!

I have simple table with fields:

Country	month	Sale
England	201201	14 625
England	201202	18 733
England	201203	24 169
England	201204	22 171
England	201205	22 586
England	201206	25 032
England	201207	28 343
England	201208	24 971
England	201209	25 826
England	201210	24 560
England	201211	15 207

and i want add object like this:

Country	month	Sale
England	201211	= sum of last 3 month

problem is - when i select 201211 another monthes just disappear from my sum.

is anybody know what i missed?

[jagannalla]

Hello,

Change your expression to =Sum({<Month =, here the set analysis what you develped to get last 3 months>}Sales)

[#3]

Hi, Jagan Nalla!

Im only in step - getting month that = moth-3

if(Right(month,2)>3,month - 3,left(month,4)-1&12+(Right(month,2) - 3))

(please sea attachment)

i have:

Country	month	Sum (Sale)	3month
England	201201	14625	201110
England	201202	18733	201111
England	201203	24169	201112
England	201204	22171	201201
England	201205	22586	201202
England	201206	25032	201203
England	201207	28343	201204
England	201208	24971	201205
England	201209	25826	201206
England	201210	24560	201207
England	201211	15207	201208

exemp. last row:  my month is 201211 and 3month ago is 201208

and now i need formula, that sum all sales between 201208 and 201211

in spite of: selected those data or not

[Gysbert_Wassenaar]

You can do this by joining every month with the months of its three month period and sales for those months. See attached example.

[#5]

Hi, Gysbert!

Thank you for your help!

How can i do this joining? Only when i load data?

incoming data sourse has more than 900 000 rows