DateRange in X++ query

Hi,

I need to select some data based on last successful run of a particular batch job. for Example:

    select CustTable 

        where CustTable.createdDateTime > 'last run date of the bacth'  && CustTable.createdDateTime < systemDateGet() 

I need to get all customers that were created since the batch ran last time until current run.

Question: 

1) How do i get the last run date for a batch job?
2) How do i mention the date range so that i don't miss any records?