Number the occurence of the field value in the script

[ziabobaz]

I have a table with Date and Item, sorted asc by Date

I need to put the number of occurence of the Item, as on the picture.

Please, help, I am stuck.

[sunny_talwar]

d seems to be appearing for the first time, why is the occurrence column showing 4?

[ziabobaz]

sorry, my mistake

D is '1'

[PV · Accepted solution]

Order(Asc) your data by Date and Item and derive the occurrence column as below.
if(Peek(Item)=Item, Peek(Occurrence)+1,1) as Occurrence

[ziabobaz]

Ordered by Item, then Date - it worked, thank you!