1. Use one or more proc SQL steps to find out whether the ISBN numbers were issued chronologically. In other words, is it possible to have a lower ISBN number than a previously published book? You may need to use the monotonic() function. There may need to involve more than 2 datasets.

The below table contains the list of all six (6) datasets and their individual variables. Bolded variable names represent common variables with other datasets.

Customers	Items	List	Orders	Prices	SalesRep
fname	orderno	bookid	salesid	bookid	id
lname	bookid	title	custid	datefirst	name
address1	dateship	author	orderno	price	salesid
city	quantity	author2	dateord	datelast
stcode		yearpub
zip		isbn
custid
phone