One of the probably most unnerving things in databases is dealing with NULLs, especially when comparing data. The necessary logic to deal with NULLs can lead to very verbose code – but if you’re using Oracle, there is a very neat function you can use.
SQLcl is a great tool, but it has its problems when it comes to environments other than English/US.
I show a couple of Problems and Strangenesses here and give examples how to work around them.
Sometimes we have data that is not split into columns and rows, but SQL can only really thrive on structured data.
But thanks to recursive queries we can split any string into rows – with pure SQL.