Originally Posted by narutoman

LibraryDB is a database system that keeps track of information concerning the books and their circulation in an imaginary library.

Disclaimer: The data that populates the database are artificially constructed and by no means correspond to actual real-world data.
The schema for the LibraryDB database is given below.

borrow(transactionID, personID*, borrowdate, duedate, returndate)
author(authorID, firstname, middlename, lastname)
book_copy(bookID, bookdescID*)
book(bookdescID, title, subtitle, edition, voltitle, volnumber, language, place, year, isbn, dewey, subjectID*)
borrow_copy(transactionID*, bookID*)
person(personID, firstname, middlename, lastname, address, city, postcode, phonenumber, emailaddress, studentno, idcardno)
publisher(publisherID, publisherfullname)
written_by(bookdescID*, authorID*, role)
published_by(bookdescID*, publisherID*, role)
subject(subjectID, subjecttype)

The primary keys are underlined. The foreign keys are denoted by asterisks (*). Description of the schema

• person -- keeps track of the people who borrow books from the library. The attributes contain personal and contact information.
• author -- keeps track of personal information about authors.
• publisher -- keeps track of the publisher information. To make simple, most of the attributes have been truncated in the sample database.
• subject -- this relation keeps information about the subjects on which the library collection have books (such as Mathematics, Database, etc)
• book -- contains information about the books that are available in the library. Every book can have one or more physical copies in the collection. Each book can have one or more authors and it is published by one or more publishers.
• book_copy -- keeps track of the physical copies of the books in the library collection.
• borrow -- keeps track of the check-ins and check-outs of the books. Every transaction is done by one person, however may involve with one or more book copies. If there is no return date, it means the book has been checked out but not returned.
• written_by -- associates books with authors. A book may be associated with several authors and an author may be associated with several books. There is also an attribute 'role' that specifies the role of the author for the book (author/ editor/ translator/ etc).
• published_by -- associates publishers with books. There is an attribute 'role' here too.
• borrow_copy -- associates physical copies of books with a transaction. Members are allowed to borrow several books in a single transaction.

I am not sure about how to do this question below
List the full names of publishers who have not published books on ``Databases".

1. Write your query using NOT IN clause.
2. Write your query using NOT EXISTS clause.

can someone please tell me how to do this one..

Thank you..