postgresql - 在 Postgresql 中创建最近 12 个月的表

Question

我正在尝试创建一个看起来像这样的表(过去 12 个月的表)

month, year
10, 2016
9, 2016
8, 2016
7, 2016
6, 2016
5, 2016
4, 2016
3, 2016
2, 2016
1, 2016
12, 2015
11, 2015

我的代码看起来像这样:

select date_part('month', current_date) as order_month,
select date_part('year', current_date) as order_year
union all
select date_part('month', current_date - interval '1 month') as order_month,
select date_part('year', current_date - interval '1 month') as order_year
union all
...

有没有比使用 11 个并集更简洁的写法？

Answer 1

generate_series(start, stop, step) 将很有用，这样

SELECT
    EXTRACT('month' FROM d) AS month,
    EXTRACT('year' FROM d) AS year
FROM
    GENERATE_SERIES(
        now(),
        now() - interval '12 months',
        interval '-1 month'
    ) AS d
;