I am looking on this last patch. I talked about the name of this command with more people, and the name "rotate" is unhappy. The correct name for this visualization technique is "crosstab" (see google "crosstab"). The conflict with our extension is unhappy, but using "rotate" is more worst - (see google "rotate"). The term "rotate" is used less time (related to topic), and usually with zero informed people. More, in attached doc, the word "crosstab" is pretty often used, and then the word "rotate" has not sense.
The important question is sorting output. The vertical header is sorted by first appearance in result. The horizontal header is sorted in ascending or descending order. This is unfriendly for often use case - month names. This can be solved by third parameter - sort function.
