If statement using Peek

[ksharpes]

Within Script I wish to use the following formula

if([Stock Qty]-[Sales Qty (All)]>Peek([Stock Qty],-1),'Restocked','') as RestockedEVER

Below is my current script which I thought should work however i only get null values for [RestockedEVER]

NEWTABLEx:
Load Item_ID,
[Stock Qty],
[Sales Qty (All)],
[Reporting Date]

Resident Data_Values_New_2
order by [Item_ID], [Reporting Date];

NEWTABLEy:
NoConcatenate Load Item_ID,
[Reporting Date],
if([Stock Qty]-[Sales Qty (All)]>Peek([Stock Qty],-1),'Restocked','') as RestockedEVER

Resident NEWTABLEx;

NEWTABLE2:
mapping Load Item_ID,
MAX(RestockedEVER) As RestockedEVER
Resident NEWTABLEy
Group by Item_ID;

Example Data

Item_ID	Stock Qty	Sales Qty (All)	Reporting Date
1	100	0	31/01/2019
1	90	10	28/02/2019
1	120	10	31/03/2019
1	110	10	30/04/2019
1	100	10	31/05/2019
2	100	0	31/01/2019
2	90	10	28/02/2019
2	120	10	31/03/2019
2	110	10	30/04/2019
2	100	10	31/05/2019
3	100	10	31/01/2019
3	90	10	28/02/2019
3	80	10	31/03/2019
3	70	10	30/04/2019
3	60	10	31/05/2019
4	100	10	31/01/2019
4	90	10	28/02/2019
4	80	10	31/03/2019
4	70	10	30/04/2019
4	60	10	31/05/2019

[lorenzoconforti · Accepted solution]

Instead of  Peek([Stock Qty],-1) use Previous([Stock Qty])