you can do one thing:
1.first load the data in ascending order of created date:
load * from tablename order by created date asc;
2. create a variable in which you fetch the minimum and maximum value:
let mindate = peek('createdDate',0,'tablename');
let maxdate = peek('createdDate',-1,'tablename');
when you load the data in ascending order then your first value is minimum and last value is maximum.
hope it will help.