这个分析函数挺好用的呀，否则只能内嵌一个子查询，非常难看

modb=# select count(distinct col2) OVER (PARTITION BY col1) from tab1;
ERROR: DISTINCT is not implemented for window functions
LINE 1: select count(distinct col2) OVER (PARTITION BY col1) f...
^
CONTEXT: referenced column: count

不知后续是否会支持？