For the purpose of this recipe, we will be using an inline data load that contains shipment details for each customer. Load the following script in the Qlik Sense Data load editor:

SalesTemp: 
LOAD DATE(Date#(DeliveryDate,'DD/MM/YYYY')) AS DeliveryDate, 
DATE(Date#(ShipmentDate,'DD/MM/YYYY')) AS ShipmentDate, 
Invoiceno.,Customer,Month,Sales INLINE [ 
Invoiceno.,Customer,Month,DeliveryDate,ShipmentDate,Sales 
101,ABC,Jan,01/01/2015,29/12/2014,10000 
102,ABC,Feb,02/02/2015,25/01/2015,10000 
103,ABC,Mar,03/03/2015,02/03/2015,12000 
104,ABC,Apr,04/04/2015,24/01/2015,10000 
105,DEF,Feb,03/02/2015,03/02/2015,25000 
106,DEF,Mar,25/03/2015,21/03/2015,25000 
107,DEF,Apr,18/04/2015,14/04/2015,25000 
108,GHI,Jan,24/01/2015,18/01/2015,8500 
109,GHI,Mar,14/03/2015,09/03/2015,7000 
110,GHI,Jun,06/08/2015,07/06/2015,5000 
]; 
 
 
Sales: 
LOAD * , 
IF(num(DeliveryDate)-num(ShipmentDate)>=0 AND 
Num(DeliveryDate)-num(ShipmentDate)<5 ,1, 
IF(num(DeliveryDate)-num(ShipmentDate)>=5 AND 
Num(DeliveryDate)-num(ShipmentDate)<25 ,2,3)) AS 
   OntimeLateFlag 
RESIDENT SalesTemp; 
DROP TABLE SalesTemp;