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 use it.
That's why I decided to write a piece on window functions. How they work and what they can be used for.
On 1st of Februyary, Takahiro Itagaki committed a patch by Pavel Stehule which adds string_agg aggregate:
Log Message: ----------- Add string_agg aggregate functions. The one argument version concatenates the input values into a string. The two argument version also does the same thing, but inserts delimiters between elements. Original patch by Pavel Stehule, reviewed by David E. Wheeler and me.