sql - 在 PostgreSQL 中创建数据透视表

Question

我有一个包含以下信息的表格:

现在我需要像这样做枢轴:

有人能帮忙吗？

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;