根据另一个表的 logtime 减去或添加数据

Question

所以目前我有 2 个表，称为列表和日志表。列表表包含产品参考号及其当前状态。所以假设如果它的状态是当前发布并且它已售出，则状态更新为已售出。这里是参考号。此表中的内容是唯一的，因为 1 个产品的状态可以更改。

现在我有另一个名为 Logs 的表，该表记录了特定产品（由 refno 引用）在特定时间范围内发生的所有状态更改。假设 Product 带有 refno。 5 是在 10 月 1 日发布并在 10 月 2 日售出，日志表将显示为：

Refno	status_from	status_to	logtime
5	Stock	Publish	2021-10-01
5	Publish	Sold	2021-10-02

这是我的表格目前的样子：

列表表格：('D'=>'Draft','N'=>'Action','Y'=>'Publish')

我使用以下语句获取的日志表：

SELECT refno, logtime, status_from, status_to FROM ( 
SELECT refno, logtime, status_from, status_to, ROW_NUMBER() OVER(PARTITION BY refno ORDER BY logtime DESC)
AS RN FROM crm_logs WHERE logtime < '2021-10-12 00:00:00' ) r 
WHERE r.RN = 1 UNION SELECT refno, logtime, status_from, status_to
FROM crm_logs WHERE logtime <= '2021-10-12 00:00:00' AND logtime >= '2015-10-02 00:00:00'
ORDER BY `refno` ASC

日志表会在每次状态更改时创建一条新记录，并将当前时间戳作为日志时间传递，而列表表会更改/更新状态并更新其 update_date。现在要获取截至今天的总房源，我使用以下语句：

SELECT SUM(status_to = 'D') AS draft, SUM(status_to = 'N') AS action, SUM(status_to = 'Y') AS publish FROM `crm_listings`

这将返回截至当天状态的所有计数数据。

现在这让我感到困惑。所以假设今天的计数是 10，明天是 15，我想检索昨天存在的总数（10）。因此，为此我要做的是取今天的总数（15）并减去昨天和今天之间产品更改为草稿的所有地方（清单表中今天的总数 - count(*) where status_to='来自日志表的操作）。反之亦然，如果昨天是 10，今天是 5，它应该添加日志表中 status_from 列中的值

注意：Refno 在我的日志表中不是唯一的，因为具有相同 refno 的产品可以标记为发布 1 天并取消发布另一个，但它在我的列表表中是唯一的。

到 dbfiddle 的链接：https://dbfiddle.uk/?rdbms=mysql_8.0&fiddle=01cb3ccfda09f6ddbbbaf02ec92ca894

Answer 1

我相信它可以被简化或更好。但这是我的查询和逻辑：

1. 我找到了每个 refno 的 status_changes 并计算了从所需日期到现在的总变化：

---

select status_logs, sum(cnt_status) to_add from (
SELECT 
status_to as status_logs, -1*count(*) cnt_status
FROM logs lm
where
id = (select max(id) from logs l where l.refno = lm.refno) and 
logtime >= '2021-10-01 00:00:00'
group by status_to
union all 
SELECT 
status_from, count(*) cnt_status_from
FROM logs lm
where
id = (select max(id) from logs l where l.refno = lm.refno) and
logtime >= '2021-10-01 00:00:00'
group by status_from ) total_changes
group by status_logs

---

1. 我通过转换列表表键匹配列表表和日志表之间的键：

---

select
case status
when 'D' THEN 'Draft'
when 'A' THEN 'Action'
when 'Y' THEN 'Publish'
when 'S' THEN 'Sold'
when 'N' THEN 'Let'
END status_l ,COUNT(*) c
from listings
group by status

---

1. 我加入了他们并将计算结果添加到当前数据的总和中。

---

4. 我必须使用完全外连接，所以我有一个左连接和一个右连接，具有相同的子查询。

最后我使用 distinct ，因为它会为每个连接查询生成相同的结果，并使用 ifnull 将其他表的状态带到另一列。

select distinct IFNULL(status_l, status_logs) status, counts_at_2021_10_01
  from (select l.*,
               logs.*,
               l.c + ifnull(logs.to_add, 0) counts_at_2021_10_01
          from (select case status
                         when 'D' THEN
                          'Draft'
                         when 'A' THEN
                          'Action'
                         when 'Y' THEN
                          'Publish'
                         when 'S' THEN
                          'Sold'
                         when 'N' THEN
                          'Let'
                       END status_l,
                       COUNT(*) c
                  from listings
                 group by status) l
          left join (
                    
                    select status_logs, sum(cnt_status) to_add
                      from (SELECT status_to as status_logs,
                                    -1 * count(*) cnt_status
                               FROM logs lm
                              where id = (select max(id)
                                            from logs l
                                           where l.refno = lm.refno)
                                and logtime >= '2021-10-01 00:00:00'
                              group by status_to
                             union all
                             SELECT status_from, count(*) cnt_status_from
                               FROM logs lm
                              where id = (select max(id)
                                            from logs l
                                           where l.refno = lm.refno)
                                and logtime >= '2021-10-01 00:00:00'
                              group by status_from) total_changes
                     group by status_logs) logs
            on logs.status_logs = l.status_l
        union all
        select l.*,
               logs.*,
               l.c + ifnull(logs.to_add, 0) counts_at_2021_05_01
          from (select case status
                         when 'D' THEN
                          'Draft'
                         when 'A' THEN
                          'Action'
                         when 'Y' THEN
                          'Publish'
                         when 'S' THEN
                          'Sold'
                         when 'N' THEN
                          'Let'
                       END status_l,
                       COUNT(*) c
                  from listings
                 group by status) l
         right join (
                    
                    select status_logs, sum(cnt_status) to_add
                      from (SELECT status_to as status_logs,
                                    -1 * count(*) cnt_status
                               FROM logs lm
                              where id = (select max(id)
                                            from logs l
                                           where l.refno = lm.refno)
                                and logtime >= '2021-10-01 00:00:00'
                              group by status_to
                             union all
                             SELECT status_from, count(*) cnt_status_from
                               FROM logs lm
                              where id = (select max(id)
                                            from logs l
                                           where l.refno = lm.refno)
                                and logtime >= '2021-10-01 00:00:00'
                              group by status_from) total_changes
                     group by status_logs) logs
            on logs.status_logs = l.status_l) l