在PostgreSQL中创建数据透视表

Question

我有一个包含以下信息的表：

现在我需要像这样枢轴旋转：

有人可以帮忙吗？

Answer 1

您可以使用条件聚合：

select hk_district,
       sum(complaint_no) filter (where month = '201801') as compaints_201801,
       sum(complaint_no) filter (where month = '201802') as compaints_201802,
       sum(complaint_no) filter (where month = '201803') as compaints_201803
from t
group by hk_district;