如何創建一個 SQL 查詢，該查詢返回超過一周的列過濾條目？

Question

我有一個 data.table 使用 SQL 具有以下相關列：

• customer_registration：每個客戶在申請獲取產品時創建的 8 位客戶代碼
• state：客戶所在的state
• 縣：客戶居住的縣
• application_date：客戶發送訂單接收申請的日期，格式為 MM/DD/YYYY
• product_issued_date：客戶申請的產品實際發送給他們的日期，格式為MM/DD/YYYY

目前我的查詢成功返回列，除了每個縣未發送的申請數量和 state 有客戶外，我還可以在其中看到申請總數

我的問題：我正在嘗試創建一個名為“7 天前已接受未發送的應用程序”的新列，該列提供當前日期前一周已發送應用程序且縣和 state 未發送任何產品的應用程序數量. 有沒有人對如何做到這一點有任何建議？

SELECT 
    state,
    county,
    COUNT (CASE WHEN customer_registration IS NOT NULL THEN 1 END) AS "Accepted Apps Total",
    COUNT (CASE WHEN customer_registration IS NOT NULL AND product_issued_date IS NULL THEN 1 END) AS "Unmailed Apps Total", /* below is where I want to write the code to determine unissued products that have been applied for in more than a week */
    COUNT() AS 'Unsent Apps Accepted 7+ Days Ago'
FROM
    public.product_data
GROUP BY 
    state, county
ORDER BY 
    state, county

Answer 1

這里對application_date列的類型有些疑惑：是DateTime還是varchar。 如果您發現自己擔心格式為 SQL 的日期值，那么您的架構就出現了嚴重錯誤！

假設正確的DateTime選項超過錯誤和損壞的varchar選項，您可以使用conditional aggregation 。 到底是什么樣子取決於您使用的是哪種數據庫產品（每個產品的日期函數都略有不同）。 Sql 服務器看起來像這樣：

SELECT 
   state
   ,county
   ,COUNT (case when customer_registration is not null then 1 end) as "Accepted Apps Total"
   ,COUNT(case when customer_registration is not null and product_issued_date is null then 1 end) as "Unmailed Apps Total" /* below is where I want to write the code to determine unissued products that have been applied for in more than a week */
   ,SUM(CASE WHEN 
            application_date < DATEADD(day, -7, current_timestamp) AND product_issued_date IS NULL 
        THEN 1 ELSE 0 END) as [Unsent Apps Accepted 7+ Days Ago]
FROM public.product_data
GROUP BY state, county
ORDER BY state, county