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Oracle PL/SQL (Procedural Language/Structured Query Language) resources, news, and support articles.

Relations as Finite Varieties

It is common wisdom that database field is firmly grounded in the two math disciplines: predicate logic and set theory. However, neither logic nor set theory are dominant math subjects. Just counting tags at can give rough idea of the importance of an individual math topic, and it is evident that algebraic geometry governs the math world. This field is so rich that it spawned new sub-fields, such as category theory.

Oracle 12c Offset & Rows

Oracle Database 12c provides a limit syntax in SQL for a query with the following clause:

Excel PowerPivot & DAX

I’ve worked with every release of Microsoft Excel, and I know it takes effort to keep up to date with certain releases. Clearly, the Data Analysis eXpression (DAX) Language introduced in Excel 2010 went unnoticed by many, which was sad. DAX is truly a powerful extension to the analytical and modeling approaches in Microsoft Excel.

23 December Quiz Now Available

For those of you checking for news on the PL/SQL Challenge site via the blog (and not the plsqlchallenge twitter account, which we encourage you to follow):

The quiz for 23 December is now being displayed properly.

Our apologies for the invalid image error and display.

All answers submitted prior to 13:45 were removed, so you can take the quiz again without simply guessing.

If we end up with 475+ answers for the day, I probably will not void the results.

Improving Website Performance: An Update

I announced earlier this week that I was suspending all work on new features until we improved the performance on the site.

Since then we have done the following:

Christmas Break

update sqlfail
set next_post_date = date '2014-01-06';
I’m taking a bit of a break over Christmas while I spend time with my daughter and her grandparents. Thanks to everyone who follows this site, hope you have a great Christmas/festive time and 2014 is everything you hope for. :)
In the meantime, there’s a message hidden in the SQL below for you (note, you’ll need to run this on to guarantee it works):

OUT Parameter Trick

Raja asked a question but unfortunately, I was buried in the final aspects of the write of the new Oracle Database 12c PL/SQL Programming book. He wanted to know how to pass an object type as an OUT-only mode parameter from a procedure.

WITH Clause Functions

A neat feature of Oracle Database 12c is the ability to put PL/SQL functions inside SQL WITH statements. It’s covered in Chapter 2 on new SQL and PL/SQL features of the Oracle Database 12c PL/SQL Programming. There’s a trick though, you must disable the SQLTERMINATOR before creating the statement or accessing it, like:

PL/SQL Challenge Website Now Available

Just in time for Tuesday!


Well, you know how you just sometimes have one of those days?

This was one of mine.

I am still analyzing the full extent of my stupidity and incompetence (and I fear the results may be classified).

But I can say this:

First of all, thank you, John Scott, for being available and so, well, non-judgmental, as you once again bailed me out.

Poor, Sad Website: Voiding Today's Quiz

At 9:45 AM Chicago time, the PL/SQL Challenge website became unresponsive. It looks like we were and are being hammered by bots. We have been unable to stop the onslaught and so after a few hours of on again, off again access, I must announce with great sadness that we will void the results for today's quiz.

This means they will not be included in rankings for the quarter.

Now, having said that, I plan - when the site and backend become available again - to see how easily we can extend the end date for today's tomorrow (make it a "two day quiz").

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