2

我有一个表“变量”和一个表“variables_history”，如下

create table variables
( 
    variables_id number,
    variables_name varchar2(50),
    variables_value varchar2(50),
    variables_updated_at timestamp
);


create table variables_history
( 
    variables_id number,
    variables_name varchar2(50),
    variables_value varchar2(50),
    variables_hist_updated_at timestamp
);

历史记录由触发器生成，如下所示。

CREATE OR REPLACE EDITIONABLE TRIGGER "myuser"."trigger_variables_update" 
  AFTER UPDATE ON myuser.variables
  REFERENCING NEW AS NEW OLD AS OLD
  FOR EACH ROW

BEGIN
  IF :old.variables_value <> :new.variables_value THEN
    INSERT INTO myuser.variables_history
      (variables_id,
       variables_name,
       variables_value,
       variables_hist_updated_at
    VALUES
      (variables_id,
       :old.variables_name,
       :old.variables_value,
       old.variables_updated_at);
  END IF;
END trigger_variables_update;

我还有一张桌子，上面有所有的维护

create table maintenance
( 
    maintenance_id number,
    maintenance_status varchar2(20),
    maintenance_date timestamp
);

我需要根据 maintenance_date 和 variables_updated_at 或 variables_hist_updated_at 的变量生成带有 maintenance_price 的输出

像这样


WITH variables_data as
( SELECT 1 variables_id, 'maintenance_price' variables_name, '30.00' variables_value, '2020-08-01 05:00:00.000' variables_updated_at from dual),

variables_history_data as
(
SELECT 1 variables_id, 'maintenance_price' variables_name, '15.90' variables_value, '2019-10-01 11:30:00.000' variables_hist_updated_at from dual union all
SELECT 1 variables_id, 'maintenance_price' variables_name, '10.50' variables_value, '2020-01-01 01:00:00.000' variables_hist_updated_at from dual union all
SELECT 1 variables_id, 'maintenance_price' variables_name, '20.30' variables_value, '2020-05-01 12:30:00.000' variables_hist_updated_at from dual
),

maintenance_data as
(
SELECT 1 maintenance_id, 'COMPLETE' maintenance_status, '2019-02-01 00:30:00.000' maintenance_date from dual union all
SELECT 2 maintenance_id, 'COMPLETE' maintenance_status, '2019-05-01 01:30:00.000' maintenance_date from dual union all
SELECT 3 maintenance_id, 'COMPLETE' maintenance_status, '2019-11-01 02:30:00.000' maintenance_date from dual union all
SELECT 4 maintenance_id, 'COMPLETE' maintenance_status, '2020-07-10 05:30:00.000' maintenance_date from dual union all
SELECT 5 maintenance_id, 'FAILED' maintenance_status, '2020-08-02 11:30:00.000' maintenance_date from dual
SELECT 6 maintenance_id, 'COMPLETE' maintenance_status, '2020-08-20 11:30:00.000' maintenance_date from dual
)

Select 
    m.maintenance_id,
    to_char(m.maintenance_date, 'yyyy/mm/dd') as maintenance_date
    v.variables_value
from 
    maintenances m
    join variables v on m.maintenance_date >= v.variables_updated_at
    join variables_history vh on m.maintenance_date < variables_hist_updated_at
        where maintenance_status = 'COMPLETE';

这个查询只是一个例子，我知道它错了

我需要这样的输出（并考虑变量可能有新的更新）。“variable_value”需要是生成维护时的值。

maintenance_id | maintenance_date | variables_value |
---------------+------------------+-----------------+
            1  |        2019-02-01|           15.90 |
---------------+------------------+-----------------+
            2  |        2019-05-01|           15.90 |
---------------+------------------+-----------------+
            3  |        2019-11-01|           10.50 |
---------------+------------------+-----------------+
            4  |        2020-07-10|           20.30 |
---------------+------------------+-----------------+
            6  |        2020-08-20|           30.00 |
---------------+------------------+-----------------+
4

2 回答 2

1

据我了解您的数据（并在 Matthew McPeak 的帮助下），历史表存储价格过时的日期，而另一方面，“实时”表存储价格生效的日期。

您可以通过两个横向连接来解决此问题：

select 
    m.maintenance_id,
    to_char(m.maintenance_date, 'yyyy/mm/dd') as maintenance_date,
    v.*,
    vh.*,
    coalesce(v.variables_value, vh.variables_value) as variables_value
from maintenances m
outer apply(
    select v.variables_value
    from variables_data v
    where v.variables_updated_at <= m.maintenance_date
) v
outer apply (
    select vh.variables_value
    from variables_history_data vh
    where vh.variables_hist_updated_at > m.maintenance_date
    order by vh.variables_hist_updated_at
    fetch first 1 row only
) vh
where m.maintenance_status = 'COMPLETE'
order by 1;

对于您的示例数据，查询返回：

MAINTENANCE_ID | 维护_日期 | VARIABLES_VALUE
-------------: | :--------------- | --------------:
             1 | 2019/02/01 | 15.9
             2 | 2019/05/01 | 15.9
             3 | 2019/11/01 | 10.5
             4 | 2020/07/10 |            无效的
             6 | 2020/08/20 | 30

请注意，您的示例数据中存在故障。历史表中应该有一行的时间戳与实时数据的当前时间戳相对应 - 因此，maintenance_id 4与任何内容都不匹配。

于 2020-08-27T16:55:41.460 回答
0

您可以使用UNION ALL来组合表格，然后使用LAG/LEAD来查找最近的（或下一个）值：

SELECT *
FROM   (
  SELECT maintenance_id,
         COALESCE(
           variables_value,
           LAG( variables_value, 1 ) IGNORE NULLS OVER ( ORDER BY maintenance_date ),
           LEAD( variables_value, 1 ) IGNORE NULLS OVER ( ORDER BY maintenance_date )
         ) AS variables_value,
         maintenance_date
  FROM   (
    SELECT maintenance_id,
           NULL AS variables_value,
           maintenance_date
    FROM   maintenances
    WHERE  maintenance_status = 'COMPLETE'
    UNION ALL
    SELECT NULL,
           variables_value,
           variables_updated_at
    FROM   variables
    UNION ALL
    SELECT NULL,
           variables_value,
           variables_hist_updated_at
    FROM   variables_history
  )
)
WHERE maintenance_id IS NOT NULL;

其中，对于您的示例数据：

CREATE TABLE variables ( variables_id, variables_name, variables_value, variables_updated_at ) as
SELECT 1, 'maintenance_price', 30.00, TIMESTAMP '2020-08-01 05:00:00.000' from dual;

CREATE TABLE variables_history ( variables_id, variables_name, variables_value, variables_hist_updated_at ) as
SELECT 1, 'maintenance_price', 15.90, TIMESTAMP '2019-10-01 11:30:00.000' from dual union all
SELECT 1, 'maintenance_price', 10.50, TIMESTAMP '2020-01-01 01:00:00.000' from dual union all
SELECT 1, 'maintenance_price', 20.30, TIMESTAMP '2020-05-01 12:30:00.000' from dual;

CREATE TABLE maintenances ( maintenance_id, maintenance_status, maintenance_date ) as
SELECT 1, 'COMPLETE', TIMESTAMP '2019-02-01 00:30:00.000' from dual union all
SELECT 2, 'COMPLETE', TIMESTAMP '2019-05-01 01:30:00.000' from dual union all
SELECT 3, 'COMPLETE', TIMESTAMP '2019-11-01 02:30:00.000' from dual union all
SELECT 4, 'COMPLETE', TIMESTAMP '2020-07-10 05:30:00.000' from dual union all
SELECT 5, 'FAILED',   TIMESTAMP '2020-08-02 11:30:00.000' from dual union all
SELECT 6, 'COMPLETE', TIMESTAMP '2020-08-20 11:30:00.000' from dual;

输出：

MAINTENANCE_ID | 变量值 | 维护_DATE            
-------------: | --------------: | :----------------------------
             1 | 15.9 | 01-FEB-19 00.30.00.000000000
             2 | 15.9 | 19 年 5 月 1 日 01.30.00.000000000
             3 | 15.9 | 19 年 11 月 1 日 02.30.00.000000000
             4 | 20.3 | 20 年 7 月 10 日 05.30.00.000000000
             6 | 30 | 20-8-20 11.30.00.000000000

如果你交换LAGand LEAD（更喜欢下一个值而不是前一个值）：

SELECT *
FROM   (
  SELECT maintenance_id,
         COALESCE(
           variables_value,
           LEAD( variables_value, 1 ) IGNORE NULLS OVER ( ORDER BY maintenance_date ),
           LAG( variables_value, 1 ) IGNORE NULLS OVER ( ORDER BY maintenance_date )
         ) AS variables_value,
         maintenance_date
  FROM   (
    SELECT maintenance_id,
           NULL AS variables_value,
           maintenance_date
    FROM   maintenances
    WHERE  maintenance_status = 'COMPLETE'
    UNION ALL
    SELECT NULL,
           variables_value,
           variables_updated_at
    FROM   variables
    UNION ALL
    SELECT NULL,
           variables_value,
           variables_hist_updated_at
    FROM   variables_history
  )
)
WHERE maintenance_id IS NOT NULL;

然后输出是：

MAINTENANCE_ID | 变量值 | 维护_DATE            
-------------: | --------------: | :----------------------------
             1 | 15.9 | 01-FEB-19 00.30.00.000000000
             2 | 15.9 | 19 年 5 月 1 日 01.30.00.000000000
             3 | 10.5 | 19 年 11 月 1 日 02.30.00.000000000
             4 | 30 | 20 年 7 月 10 日 05.30.00.000000000
             6 | 30 | 20-8-20 11.30.00.000000000

db<>在这里摆弄

于 2020-10-19T22:33:07.703 回答