Category: SQL

The core Formula One data could be represented in a graph like this: Drivers compete in races that are hosted on circuits. A result is achieved by the driver …

I bet you are used to relational data structures that you query using SQL. And so do I. And there is nothing in terms of data that a good …

In an earlier article, I showed how to quickly get going with an Oracle Database 23c Free instance in a Gitpod workspace – cloud based, ephemeral, quick start, zero …

  preparation for migrating data to Oracle Virtual Private Database Introduction Recently I was part of a team involved in the preparation of migration data belonging to multiple business …

A nice SQL challenge was presented to me by a colleague. The challenges basically consisted of this table. A table contains records that describe login events. Each record has …

So here it is Oracle announces a license audit, some urgency kicks in and this familiar but also really serious question comes down from management: “Are we using any …

Creating or modifying an Oracle Database user password can be done by using any standard password generator you can find on the WEB. But I wanted a password to …

Topic of this blog is a nice new feature in 12c, not the plsql package I built that’s using it. So here’s the story.. For one of our customers …

Maarten wrote a post on Virtual Columns in the oracle database. I read a blogpost on preventing people issuing SELECT * on a table. This was done in a …

Some time ago I was asked to assist in fixing or at least finding the cause of a performance problem. The application ran fine until the Virtual Private Database …

Last week I read this blogpost by Scott Wesley. In this post he describes that he uses a custom aggregate function to create large JSON-strings. And for that he …

Question: We have customers who want to work with different database schemas and we want to determine dynamically – depending on a choice during or after login – which …

Once you are able to show the xml version of the alert log as data in database table Alert_XML, it would be nice to checkout the errors with accompanying …

By mapping an external table to some text file, you can view the file contents as if it were data in a database table. External tables are available since …

Oracle Database 7.3 was the first to support inline views – using the select * from (select * from) syntax. Oracle Database 9i added the with clause for subquery …

In a previous article, I have introduced the World Cup Football tag cloud (https://technology.amis.nl/2014/06/22/sql-challenge-dynamically-producing-a-tag-cloud-for-world-cup-football-matches/). I have shown how tags can be associated with football matches, both explicitly and implicitly …

Tag clouds are a special way to present information about a set of records. Tags are descriptive labels that are associated with specific records. A tag cloud visualizes the …

As I recently said in another blog post, the World Cup Football is such a wonderful source of data that begs to be digested using SQL in many different …

Few things lend itself so well to SQL explorations as sport related data. The imminent World Cup Football (or Soccer in some deprived parts of the world)2014 in Brazil …

During the OUGF 2014 Harmony Conference in Finland, I attended a seminar by Chris Date on Temporal Data and the Relational Model. He introduced an approach within the relational …

The speed of cars can be detected at large distance and with great accuracy using laser speed guns. How the measured speeds translate into speeding tickets depends on the …

Just a quick blog about a simple trick to select a blob across a database link, especially for a collegue of mine, Harry Dragstra. Say, you have a table …

  April is the month of the presentations and seminars for me (May and June too by the way). On Wednesday April 22nd, I will be presenting a seminar …

The Oracle 10g Database release saw an extension of the MERGE statement with a DELETE clause. That by the way makes MERGE the only statement that can fire all …

To understand how Analytical Functions are used in SQL statements, you really have to look at the four different parts of an Analytical ‘clause’: the analytical function, for example …