Set Analysis: Last Year Same Week

[semgem12]

Hello

Hope someone can help with this please.

I have a table with week numbers and sales for those weeks. The weeks take the format yyww, e.g. 1831 means week 31 of year 2018.

Within a Qlik Sense sheet I want to be able to show each week and the sales for that week as well as the sales for the same week in the previous year. E.g. an entry for 1831 might show

Week	Sales for Week	Sales Last Year
1831	100.00	95.00

meaning sales in 1831 were 100.00 and in 1731 they were 95.00.

This is just a sample of the data

LOAD * INLINE [

Week,Sales

1731,95

1732,97

1733,99

1831,100

1832,101

1833,102

etc.

];

So in a table the dimension would be Week and the Sales for Week would be sum(Sales).

I'm not sure how to get the sales for the previous year. I want to be able to do something like

sum({$<Week = {Week-100}>}Sales)

But I know I can't do this.

Can anyone think of a way to do this please?

Thanks.

[sunny_talwar]

I suggest using an The As-Of Table here to associate this yearweek to last yearweek

[YoussefBelloum]

Hi,

there is a lot of methods to get the week of the last year, but with the data you have, what you proposed "sum({$<Week = {Week-100}>}Sales)" is interesting, it is just the syntax that is incorrect..

try this expression:

=sum({$<Week = {$(=Max(Week)-100)}>}Sales)

[semgem12]

Thanks Youssef. Unfortunately that did not work. The maximum week in my data set is 1852 and the expression aggregated all the sales into week 1752 (i.e. 1852-100).

[YoussefBelloum]

it is normal, you will need one expression per year:

one

=sum(Sales)

and another one:

=sum({$<Week = {$(=Max(Week)-100)}>}Sales)

[semgem12]

Thanks but not sure I understand.....

sum({$<Week = {$(=Max(Week)-100)}>}Sales)

generates results like this

Week    LastYearSales
.

.

1750              0.00

1751              0.00  

1752          999.99

1801              0.00

1802              0.00

1803              0.00

.

.

This is because my weeks go up to 1852 and so max(week)-100 = 1752. So only 1752 has a value. Each week should show its last year's value.

[semgem12]

Thanks. I've read through the article but not sure how to apply and use it in this situation.

[YoussefBelloum]

I see, for this you should use above() function or the solution provided by stalwar1‌ above.

[sunny_talwar · Accepted solution]

Something like this?

[menta]

For previous year

sum({$<Week = {"$(=Max(Week)-100)"}>}Sales)