如何根据不同日期列中的内容计算天数差异

Question

我有一个表，它的日期时间对应于不同的状态：为每个用户点击、认领和购买。

我折叠了每个用户的记录，并将每个状态对应的每个日期时间放在他们自己的列中：clicked_date、claim_date和buy_date。我也有一个截止日期。

现在我需要另一个列来计算截止日期的天数。新列（number_days）应该总是减去deadline_date 减去clicked_date。但是，如果 clicked_date 设置为“2999-12-31”，那么它应该减去deadline_date 减去claim_date。如果clicked_date 设置为“2999-12-31”并且claimed_date 设置为=“299-12-31”，那么它应该减去截止日期减去购买日期。如果 clicked_date 设置为“2999-12-31”，claim_date 设置为“2999-12-31”，buy_date 设置为“2999-12-31”或deadline_date = '/N'，那么它应该为0。

In the examples above,
The first record should be (deadline_date - bought_date)
The second record should be (deadline_date - clicked_date) 
The third record should be 0.
The fourth record should be (deadline_date - claimed_date)
The fifth record should be (deadline_date - claimed_date) 
The fifth record should be (deadline_date - clicked_date) 

我无法制定此查询。有谁知道我如何根据点击、认领和购买的三个不同日期列中的每一个来计算天数？

我尝试了类似的方法，但它不起作用：

select 
user,
(array_agg(STATUS) within group(order by UPDATED_AT_DATETIME desc)[0])::varchar as last_status,
   coalesce(max(case when STATUS = 'clicked'  THEN UPDATED_AT_DATETIME END),'2999-12-31'::datetime) as clicked_date,
   coalesce(max(case when STATUS = 'claimed'   THEN UPDATED_AT_DATETIME END),'2999-12-31'::datetime) as claimed_date,
   coalesce(max(case when STATUS = 'bought' THEN ACCOUNT_REWARD_UPDATED_AT_DATETIME END),'2999-12-31'::datetime) as bought_date,
   **case when CLICKED_DATE <> '2999-12-31 00:00:00.000' then DATEDIFF('days', TRY_TO_TIMESTAMP(clicked_date) ,TRY_TO_TIMESTAMP(DEADLINE_DATETIME))
   when claimed_date <> '2999-12-31 00:00:00.000' then DATEDIFF('days', TRY_TO_TIMESTAMP(claimed_date) ,TRY_TO_TIMESTAMP(DEADLINE_DATETIME))
   when bought_date <> '2999-12-31 00:00:00.000' then DATEDIFF('days', TRY_TO_TIMESTAMP(bought_date) ,TRY_TO_TIMESTAMP(DEADLINE_DATETIME))
   END as number_days**
from TBL_A a
group by 1,2

Answer 1

这些规则也可以直接写成这样：

SELECT 
    clicked_date,
    claimed_date,
    bought_date,
    deadline_date,
    CASE
        WHEN clicked_date != "2999-12-31" THEN datediff(day,deadline_date,  clicked_date)
        WHEN clicked_date = "2999-12-31" THEN datediff(day, deadline_date, claimed_date)
        WHEN clicked_date = "2999-12-31" AND claimed_date = "2999-12-31" THEN datediff(day, deadline_date, bought_date)
        WHEN clicked_date = "2999-12-31" AND claimed_date = "2999-12-31" AND bought_date = "2999-12-31" THEN 0
        WHEN deadline_date = "/N" THEN 0
    END AS number_days
FROM table;

但是，第 3 条和第 4 条规则对第 2 条规则的限制更大，因此需要放在前面以便它们触发，因此您想要的代码是这样的：

SELECT 
    clicked_date,
    claimed_date,
    bought_date,
    deadline_date,
    CASE
        WHEN clicked_date != "2999-12-31" THEN datediff(day,deadline_date,  clicked_date)
        WHEN clicked_date = "2999-12-31" AND claimed_date = "2999-12-31" AND bought_date = "2999-12-31" THEN 0
        WHEN clicked_date = "2999-12-31" AND claimed_date = "2999-12-31" THEN datediff(day, deadline_date, bought_date)
        WHEN clicked_date = "2999-12-31" THEN datediff(day, deadline_date, claimed_date)
        WHEN deadline_date = "/N" THEN 0
    END AS number_days
FROM table;

或者，如果您想明确表达，可以加入排除：

SELECT 
    clicked_date,
    claimed_date,
    bought_date,
    deadline_date,
    CASE
        WHEN clicked_date != "2999-12-31" 
            THEN datediff(day,deadline_date,  clicked_date)
        WHEN clicked_date = "2999-12-31" AND claimed_date != "2999-12-31" AND bought_date != "2999-12-31" 
            THEN datediff(day, deadline_date, claimed_date)
        WHEN clicked_date = "2999-12-31" AND claimed_date = "2999-12-31" AND bought_date != "2999-12-31" 
            THEN datediff(day, deadline_date, bought_date)
        WHEN clicked_date = "2999-12-31" AND claimed_date = "2999-12-31" AND bought_date = "2999-12-31" 
            THEN 0
        WHEN deadline_date = "/N" 
            THEN 0
    END AS number_days
FROM table;

现在，如果您的“日期”是 DATES，则上述方法将起作用，但如果它们只是字符串，正如“/N”所暗示的那样，您将需要将这些字符串转换/解析为日期。喜欢：

SELECT 
    clicked_date,
    claimed_date,
    bought_date,
    deadline_date,
    CASE
        WHEN clicked_date != "2999-12-31" 
            THEN datediff(day,deadline_date::date,  clicked_date::date)
        WHEN clicked_date = "2999-12-31" AND claimed_date != "2999-12-31" AND bought_date != "2999-12-31" 
            THEN datediff(day, deadline_date::date, claimed_date::date)
        WHEN clicked_date = "2999-12-31" AND claimed_date = "2999-12-31" AND bought_date != "2999-12-31" 
            THEN datediff(day, deadline_date::date, bought_date::date)
        WHEN clicked_date = "2999-12-31" AND claimed_date = "2999-12-31" AND bought_date = "2999-12-31" 
            THEN 0
        WHEN deadline_date = "/N" 
            THEN 0
    END AS number_days
FROM table;