In our August 2008/ September 2008 issue we demonstrated the power of PostgreSQL to create median and MS Access-like first and last aggregate functions in
SQL language. In this article we shall demonstrate how to create aggregates with Python. We shall
call this function agg_plot. What it will do is plot each grouping of data and return a plot for each grouping. The steps
we covered in those articles can be applied here.
For this part, we shall use the same library we discussed in PLPython Part 3: Using custom classes, pulling data from PostgreSQL.