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The Latest

Calculating Averages Within Arbitrary Groups

Question: [Joe Celko’s Production Report Puzzle]We get a production report from work centers which has a date, center code and how many widgets were produced from each batch of raw

Nested Outer Joins

Question: [Joe Celko’s Outer (JOIN) Limits Puzzle]Gerard Manko at ARI had a problem in 1994 April. They had just switched over from Paradox to Watcom SQL. The conversion of the

What does AFX stand for?

Question: I see the term “AFX” everywhere in the MFC source code.For example, “AFX_MSG_MAP”. What does it mean? Answer: I once asked this of Jeff Harbers, one of the original

ODBC Versus SQL

Question: What are the disadvantages of ODBC versus SQL? Answer: ODBC is a generic implementation, whereas native SQL is always optimized for the database server being used. Thus, if you

Calculating and Using Averages

Question: Can I determine which employees have received a salary for a month that is more than twice the average salary in that month? I need to show:month_number, average salary,

Indexes in SQL

Question: Is it possible to set indexes between tables in SQL expression? Answer: You can establish indexes on SQL tables, but SQL indexes do not create an implied relationship between

What is the Moving Worlds proposal about?

Question: What are the key features of the Moving Worlds proposal? Answer: Moving Worlds is VRML 2.0 proposal from a consortium of companies, formed by SGI, who are interested in

Finding the Correct Row Based on Effective Date

Question: I have a table with three columns: the firstcontains the name of the currency, thesecond contains the currency rate and the third contains the actual date when thecurrency rate

Which VRML engines are available?

Question: Which rendering engines are used in VRML browsers and how do they affect my choice of browser? Answer: The library of functions that is used to create all the

Is there a preferred VRML browser?

Question: Is there a VRML browser most users prefer? If so, why? Answer: Well, if you’re Microsoft, then you may think that World View browser from Intervista Software is the

What is IBM’s VRML 2.0 proposal about?

Question: What are the key features of IBM’s VRML 2.0 proposal? Answer: Researchers at IBM Japan have proposed a reactive virtual environment. No Web references to the proposal were available

Case Sensitivity in Searches

Question: How can I ignore case when trying to SELECT allrecords that are LIKE a certain string variable? I have an employee’s name field in which the charactersare a combination

Formatting SQL Results

Question: I am trying to select data from three columns of a table listing all tables of a database. The table_name column is repeated with each separate column_namecolumn, hence the

Are there any examples of VRML 2.0 I can see now?

Question: What VRML 2.0 sites are there now? Answer: Yes, there are products available that have been developed with the same aspirations as VRML 2.0 (i.e., simulation of the real

What is Sun’s HoloWeb proposal about?

Question: What are the key features of Sun’s HoloWeb? Answer: Sun Laboratory’s HoloWeb proposal uses Java as an integrated real-time 3D animation scripting language. HoloWeb is a binary file format,

Automatically Assigning Values

Question: [Joe Celko’s Hotel Rooms Puzzle]Ron Hiner put this question on the Watcom forum on CompuServe. He had a data conversion project where he needed to automatically assign some values

Comparing Aggregate Results

Question: [Joe Celko’s Promo Puzzle]Let’s assume that you have just gotten a job as the sales manager for a department store. Your database has the following two tables. One is

Calculating Averages Using Clock Times

Question: Joe Celko’s Store Survey Puzzle]You are collecting statistical information stored by the quarter hour. What your customer wants is to get information by hour ? not on the hour.

Finding the Most Recent and Consecutive Data

Question: [Joe Celko’s Pension Plan Puzzle]Luke Tymowski, a Canadian programmer, posted an interesting problem on the MSAccess forum on CompuServe in 1994 November. He was working on a pension fund

Finding Data Based on Contents of Multiple Columns

Question: Joe Celko’s Playing the Ponies Puzzle]You have just become the database manager for Eddie Franco “the Doctor” Coddetti. He keeps records on horse races for statistical purposes and his

VRML displaying information on a Web site

Question: Is there a site where VRML is being used to display information in a unique way? Answer: Yes, the most innovative site I have come across is that of

Tax Problem Puzzle

Question: [Joe Celko’s Tax Problem Puzzle]I got this one from Richard S. Romley, via CompuServe. We were engaged in a debate about Sybase’s old T-SQL versus ANSI/ISO SQL-92. I assume

Wildcard Searches in SQL

Question: Are wildcards allowed when trying to matchthe contents of a textfield as in the following example? SELECT * FROM Database WHERE textfield = ‘B*’ Answer: Yes, but you’ll need

Sorting “Codes” within a Column

Question: I have a table that consists of numbers stored as characters.How can I sort them in numerical order? I can’t convert thisfield to numeric because some content is alpha

Solving Multiple Conditions Within a Group

Question: [Joe Celko’s Work Order Puzzle]Cenk Ersoy asked this question on the Gupta Forum on CompuServe. He has a table that looks like this: CREATE TABLE Projects (workorder CHAR(5) NOT