如何在 PostgreSQL 中合并两个查询？

Question

我想在 PostgresSQL 中编写一个查询，返回给定日期范围内的月销售额。

我有 2 个查询 - 1 个返回销售计数，另一个返回按日期范围（开始日期和结束日期）列出的月份列表

查询 1：（返回销售计数）

SELECT count(overall_sl) total_sales, count(CASE WHEN overall_sl < value_1 THEN 1 END) faled_sales
            FROM  (
                SELECT overall_sl, value_1
                FROM   combined c 
                GROUP  BY dept_name, date_updated, date, overall_sl, no_addons,  
                value_1, category_id, subcategory_id, branch_name
              ) sales;

Output:
total sales     failed_sales
----------------------------
1047            54

查询 2：（返回给定两个日期的月份列表）

WITH date_ranges AS (
    SELECT 
      min(date_trunc('month', timestamp '2018-01-01')) min_start,
      max(date_trunc('month', timestamp '2018-12-11'))  max_end
    )
    SELECT 
       ser.month::DATE as st_month,
       (date_trunc('month', ser.month::DATE) + interval '1 month' - interval '1 day')::date as end_month,

       0 as total_sales,
       0 as failed_sales
    FROM date_ranges AS dr,
         generate_series(min_start, max_end, '1 month') AS ser(month) 

Output:
st_date     end_date   total_sales    failed_sales
----------  ----------  ----------    ------------
2018-01-01  2018-01-31  0             0
2018-02-01  2018-02-28  0             0

我需要加入这些查询，如下图所示

如何在 Postgres SQL 中编写此查询？

Answer 1

你可以试试下面的

with cte as
(
SELECT count(overall_sl) total_sales, count(CASE WHEN overall_sl < value_1 THEN 1 END) faled_sales
            FROM  (
                SELECT overall_sl, value_1
                FROM   combined c 
                GROUP  BY dept_name, date_updated, date, overall_sl, no_addons,  
                value_1, category_id, subcategory_id, branch_name
              ) sales
), 
date_ranges AS 
(
    SELECT 
      min(date_trunc('month', timestamp '2018-01-01')) min_start,
      max(date_trunc('month', timestamp '2018-12-11'))  max_end
),
cte2 as
(
SELECT 
       ser.month::DATE as st_month,
       (date_trunc('month', ser.month::DATE) + interval '1 month' - interval '1 day')::date as end_month,

       0 as total_sales,
       0 as failed_sales
    FROM date_ranges AS dr,
         generate_series(min_start, max_end, '1 month') AS ser(month)
) select cte.*,cte2.* from cte join cte2 on cte.total_sales=cte2.total_sales and cte.failed_sales=cte2.failed_sales