Question

我试图插入要从中提取的表中不存在的行，它按days_to_cancel列排序，并从零开始，并有新的Year / Month项。我正在使用以下查询：

CREATE TABLE reporting.tbl_exec_retention_curve_cumulative (days_to_cancel int, cancels int, cumulative_cancels int, enroll_dt varchar(50));
SELECT rc.days_to_cancel,
       rc.cancels,
       (@run_total := CASE WHEN rc.days_to_cancel <> 0 THEN @run_total + 
       rc.cancels ELSE rc.cancels END) AS cumulative_cancels,
       LEFT(rc.client_enroll_dt,7) AS client_enroll_dt
FROM   (SELECT rc.days_to_cancel,
               SUM(CASE WHEN rc.client_status = 'CAN' THEN 1 ELSE 0 END) AS cancels,
               LEFT(rc.client_enroll_dt,7) AS client_enroll_dt
        FROM   t1.table rc
        GROUP BY 1,3
        ORDER BY 3,1
        ) rc
JOIN    (SELECT @run_total := 0) r
GROUP BY 1,4
ORDER BY 4,1;

我得到以下样本结果

days_to_cancel | cancels | cumulative_cancels | client_enroll_dt
---------------+---------+--------------------+------------------
       42      |    2    |         376        |     2019-02
       47      |    0    |         376        |     2019-02
       0       |    0    |         0          |     2019-03
       10      |    4    |         4          |     2019-03
       11      |    9    |         13         |     2019-03

所以我的目标是输入缺少的日期，并在输入那些缺少的日子的新行时，使用以前的cumulative_cancels和enroll_dt值，将0用作取消列。我已经尝试了多种方法，包括使用变量，但我一无所获。我不知道是否有可能首先考虑到行不存在。如果有问题，我使用的是MariaDB 10.0.35版。

Answer 1

我只是想像您从t1.table获取了数据，并希望将结果插入同一张表中。

我的解决方案是将结果放入临时表中，然后通过左联接查找丢失的日子。

SELECT rc.days_to_cancel,
       rc.cancels,
       (@run_total := CASE WHEN rc.days_to_cancel <> 0 THEN @run_total + 
       rc.cancels ELSE rc.cancels END) AS cumulative_cancels,
       LEFT(rc.client_enroll_dt,7) AS client_enroll_dt
--put your result into a temp table
into #temp
FROM   (SELECT rc.days_to_cancel,
               SUM(CASE WHEN rc.client_status = 'CAN' THEN 1 ELSE 0 END) AS cancels,
               LEFT(rc.client_enroll_dt,7) AS client_enroll_dt
        FROM   t1.table rc
        GROUP BY 1,3
        ORDER BY 3,1
        ) rc
JOIN    (SELECT @run_total := 0) r
GROUP BY 1,4
ORDER BY 4,1;


insert into t1.table (days_to_cancel, cancels,cumulative_cancels, client_enroll_dt)
select tm.days_to_cancel, tm.cancels, tm.cumulative_cancels, tm.client_enroll_d from #temp tm
left join t1.table rc on rc.days_to_cancel = tm.days_to_cancel
where rc.days_to_cancel is null --find out missing days

drop table #temp

插入不存在且使用先前值的行

1 个答案: