Gruber’s explanation of self-joins provides the solution:
One of the most frustrating aspects of generating PDFs from SQL is the appearance of blank spaces or the word "null" in your final document. Gruber famously dedicated a section to the three-valued logic of SQL (True, False, Unknown). martin gruber understanding sqlpdf better
Martin Gruber's "Understanding SQL" is a widely acclaimed book that provides an in-depth introduction to the world of SQL (Structured Query Language). First published in 1988, the book has undergone several revisions and updates to keep pace with the evolving SQL standards. One of the most popular formats for sharing and distributing this valuable resource is PDF (Portable Document Format). In this write-up, we'll explore how to better understand SQL using Martin Gruber's book in PDF format. First published in 1988, the book has undergone
If you are using a digital version like a PDF from the Internet Archive or other sources: If you are using a digital version like
SELECT customer_name, COALESCE(phone_number, 'N/A') as phone_number, COALESCE(last_order_date, 'No orders yet') as last_order FROM customers;