CASE expressions are the standard way to implement IF … THEN … ELSE logic in SQL statements. Oracle provides the DECODE function, which does something similar and is widely used by Oracle developers, but CASE expressions are actually more flexible… Continue Reading
This time I’m just writing to tell you a story about the WITH clause, because it is really powerful and vastly underutilized. You can read the basics about the WITH clause in my previous article about subqueries. So, this is… Continue Reading
Subqueries are a very powerfull feature of SQL, but I have seen them being misused or underused many times, and that is why I decided to write about them today. The Basics For starters, a subquery is a SELECT statement… Continue Reading
I’ve worked with Oracle databases for many years, and during this time I have seen code written by lots of different people. One thing I have noticed is that with few exceptions, people who started working with Oracle many years… Continue Reading
Oracle’s DECODE is one of the functions I find more powerful and one that over the years I have used thousands of times to solve several different kinds of problems. Here I’m going to talk a little bit about how… Continue Reading
The NVL function is very useful in a lot of different situations and is probably one of the most widely used among Oracle developers. One of the ways we can use it is to write queries that have ‘optional’ conditions.… Continue Reading
I have seen quite a few questions on internet forums and knowledge exchange sites about Oracle NVL, NVL2 and COALESCE functions for handling nulls, so I decided to write an article about them today. Those functions are actually similar, but… Continue Reading