On 25th of November, Tom Lane committed patch: Support arrays as input to array_agg() and ARRAY(SELECT ...). These cases formerly failed with errors about "could not find array type for data type". Now they yield arrays of the same element type and ...

And maybe not on the wall, but instead in your SQLz, eating your data. But a bit more seriously. Ever since PostgreSQL 8.4 we have window functions, but still I see people which do not know it or are wary to ...

On 15th of December Tom Lane committed patch by Andrew Gierth (aka RhodiumToad), which adds interesting capability: Log Message: ----------- Support ORDER BY within aggregate function calls, at long last providing a non-kluge method for controlling the order in which values are fed to ...

Finally, we got very important addons to PostgreSQL, which help with dealing with arrays. It solves a lot of problems, which were usually solved with standard cookbook code, which was in faqs, blog posts and number of examples on irc.