1. SQL Joins
FdSc in ICT

2. Structure – using student#
Borrower 7 (Pratton) has borrowed book 9 (Doing Postgraduate Research) Note: Illustrations of tables are shortened to fit on the slides

3. An inner join returns all rows that result in a match
SELECT lastname,loans.bookid
FROM borrower
INNER JOIN loans
ON borrower.borrowerid = loans.borrowerid

4. A LEFT JOIN returns all rows from the LEFT table even if there is no match in the RIGHT table
SELECT lastname,loans.bookid FROM borrower LEFT JOIN loans ON borrower.borrowerid = loans.borrowerid
Left table
Right table

5. A RIGHT JOIN returns all rows from the RIGHT table even if there is no match in the LEFT table
SELECT books.title,loans.bookid FROM loans RIGHT JOIN books ON loans.bookid = books.bookid
Left table
Right table

6. A three way LEFT join SELECT books.title, borrower.lastname FROM books
LEFT JOIN loans ON
books.bookid = loans.bookid
LEFT JOIN borrower ON
loans.borrowerid = borrower.borrowerid