March 25, 1997

What is Microsoft’s Active VRML proposal about?

Question: What are the key features of Active VRML? Answer: Microsoft’s Active VRML, is a proposal built on top Microsoft’s Direct X suite of graphics/multimedia APIs, and also incorporates Microsoft’s

How compatible are VRML browsers?

Question: If I make a VRML page, can it be read by any browser? Answer: The original idea behind VRML 1.0 was that any VRML scene should be viewable using

Finding the Top n Within a Group

Question: [Joe Celko’s Best Salesmen by Territory Puzzle]Martin Tillinger posted this problem on the MSAccess forum of CompuServe. How do you get the top three salesmen in each territory, given

How can I create VRML pages?

Question: What can I use to produce VRML, or can I write it like HTML? Answer: It is possible to write VRML as a purely text-based language, using a regular

Finding the Greatest Lower Bound

Question: [Joe Celko’s Sales Gaps Puzzle]Given a table “sales” and a column “saledate” and “customer,” is there a way to get the average number of days between sales dates for

Calculating Running Totals

Question: [Joe Celko’s Quantity on Hand Puzzle]You are now the guy in charge of the company inventory. You get requisitions that tell how many widgets people are putting into a

CHECK Constraint To Avoid Overlapping Data

Question: [Joe Celko’s Reservations Puzzle]Since I spend a lot of time this column talking about problems with the order of execution of SQL statements, it is only fair that I