时间间隔/行上的SQL求和

下面的代码

SELECT distinct DATE_PART('year',date) as year_date,
DATE_PART('month',date) as month_date,
count(prepare_first_buyer.person_id) as no_of_customers_month
FROM
(
SELECT DATE(bestelldatum)  ,person_id
,ROW_NUMBER() OVER (PARTITION BY person_id ORDER BY person_id)
FROM ani.bestellung
) prepare_first_buyer
WHERE row_number=1
GROUP BY DATE_PART('year',date),DATE_PART('month',date)
ORDER BY DATE_PART('year',date),DATE_PART('month',date)

返回此表：

| year_date | month_date | no_of_customers_month |
|:--------- |:----------:| ---------------------:|
| 2017      | 1          | 2                     |
| 2017      | 2          | 5                     |
| 2017      | 3          | 4                     |
| 2017      | 4          | 8                     |
| 2017      | 5          | 1                     |
| .         | .          | .                     |
| .         | .          | .                     |

其中，als 3是数值。 我现在需要一个新的专栏，我总结了12个月前“无客户月”的所有值。 e、 g

其中，23是2019-1年至2018-1年期间“每月无客户”的总和

---

Thx以获取帮助。

您可以使用窗口功能：

SELECT DATE_TRUNC('month', date) as yyyymm,
       COUNT(*) as no_of_customers_month,
       SUM(COUNT(*)) OVER (ORDER BY DATE_TRUNC('month', date) RANGE BETWEEN '11 month' PRECEDING AND CURRENT ROW)
FROM (SELECT DATE(bestelldatum), person_id,
             ROW_NUMBER() OVER (PARTITION BY person_id ORDER BY person_id)
      FROM ani.bestellung
     ) b
WHERE row_number = 1
GROUP BY yyyymm
ORDER BY yyyymm;

注意：这使用

date\u trunc（）

检索年/月作为日期，允许使用

range（）

。我还发现日期比把年和月分开列更方便

某些版本的Postgres不支持

范围

窗口框架。假设您有每个月的数据，您可以使用

行

：

SELECT DATE_TRUNC('month', date) as yyyymm,
       COUNT(*) as no_of_customers_month,
       SUM(COUNT(*)) OVER (ORDER BY DATE_TRUNC('month', date) ROWS BETWEEN 11 PRECEDING AND CURRENT ROW)
FROM (SELECT DATE(bestelldatum), person_id,
             ROW_NUMBER() OVER (PARTITION BY person_id ORDER BY person_id)
      FROM ani.bestellung
     ) b
WHERE row_number = 1
GROUP BY yyyymm
ORDER BY yyyymm;

---

您可以使用窗口功能：

SELECT DATE_TRUNC('month', date) as yyyymm,
       COUNT(*) as no_of_customers_month,
       SUM(COUNT(*)) OVER (ORDER BY DATE_TRUNC('month', date) RANGE BETWEEN '11 month' PRECEDING AND CURRENT ROW)
FROM (SELECT DATE(bestelldatum), person_id,
             ROW_NUMBER() OVER (PARTITION BY person_id ORDER BY person_id)
      FROM ani.bestellung
     ) b
WHERE row_number = 1
GROUP BY yyyymm
ORDER BY yyyymm;

注意：这使用

date\u trunc（）

检索年/月作为日期，允许使用

range（）

。我还发现日期比把年和月分开列更方便

某些版本的Postgres不支持

范围

窗口框架。假设您有每个月的数据，您可以使用

行

：

SELECT DATE_TRUNC('month', date) as yyyymm,
       COUNT(*) as no_of_customers_month,
       SUM(COUNT(*)) OVER (ORDER BY DATE_TRUNC('month', date) ROWS BETWEEN 11 PRECEDING AND CURRENT ROW)
FROM (SELECT DATE(bestelldatum), person_id,
             ROW_NUMBER() OVER (PARTITION BY person_id ORDER BY person_id)
      FROM ani.bestellung
     ) b
WHERE row_number = 1
GROUP BY yyyymm
ORDER BY yyyymm;