A couple of days ago, I stumbled upon SQLFiddle, a little magical website that allows you to upload a DBSchema and run queries on it, live in the browser. It also allows to share them with other users.
In the course of my work, I’ve often come across a table that has an identifier, a timestamp and a value, and these rows must be mapped to one new row containing multiple identifiers. Two typical examples of that are two identifiers defining a minimum and a maximum value timeseries that must be put into a single row entry and an entry that is built from three identified timeseries representing value, volatility and mean reversion parameters of a stochastic process.
In my earlier blog post, Oracle 10g – Pivoting data, I provided two different sql scripts to solve the first case min/max time series. You can find the SQLFiddles here:
You can even view your query’s execution plan, which is a really nice touch. I’ll take the time to share some more oracle sql statements next time in an SQLFiddle.