SQL Magic Squares – or Why the Optimizer does not like Magic
A long-time player at the Oracle Dev Gym tried his hand at generating Magic Squares using SQL. When he attempted to tune his statement a bit, he was surprised that it didn’t go a little faster as expected, rather it went from 2 minutes to…
String to DATE conversion and validation in 12.2
A new little feature in Oracle Database 12.2 is, that you can convert strings to dates without worrying about exception handling. (That goes also for converting to numbers or timestamps or other datatypes, but here I’ll concentrate on dates.) It’s just one of a ton…
A handful of articles
A little while ago a member of the Danish Oracle User Group DOUG asked if anyone had a bit of experience with use of R together with Oracle Database. I remembered an article I wrote for OTech Magazine on forecasting with R and Oracle and thought…
Row pattern matching nested within hierarchy
I’ve been playing around with MATCH_RECOGNIZE – the data pattern matching extension to SELECT that was introduced in version 12. Most examples I’ve seen have used the default AFTER MATCH SKIP PAST LAST ROW as most often the logic dictates, that when we have found…
HSQLDB Query log – Output SQL statements to log file
It’s sometimes useful (especially for debbuging) to be able to see all the SQL statements that the database runs Lots of RDBMS have this very useful feature (MySQL for example calls it query log) The HSQLDB is one of those and it can be accomplished…