Missing Records

[QlikBeginner1]

Hello,

I have an app which is a report comparing two different source systems and the GWP for each source system based off a number of dimensions.

One of the source systems assigns Policy Numbers in sequence.  Any gaps in range may indicate something has been missed.  How can I produce a table which essentially the missing numbers to indicate if there is a missing number? For example 

PC00002, PC00003, PC00004, PC00006. There would be a table which has a header of 'Missing Policies' and to show PC00005.  From PC00001 to the Max of the PolicyNumbers where the Source System = 'Acturis'. 

I hope I am making sense, any help would be greatly appreciated. 

Kind regards,

[QFabian]

Hi @QlikBeginner1 , check this please :

Data:
Load * inline [
Record
PC00002
PC00003
PC00004
PC00006
];

Record:
Load
*,
1 as Exists
Resident Data;

//Let vMin = PurgeChar(peek('Record',0,'Record'),'PC');
Let vMax = PurgeChar(peek('Record',NoOfRows('Record')-1,'Record'),'PC');

Load
'PC' & num(recno(),'00000') as Record,
0 as Exists
autogenerate ($(vMax))
Where not exists(Record,'PC' & num(recno(),'00000') );