随着时间的推移跟踪活动对象

Question

我有一个事件表（id 用作事件 ID），如下所示（另请参阅 SQL fiddle here）：

CREATE TABLE ext (
  key INT,
  id CHAR(1),
  pid INT,
  sid INT, 
  oid INT,
  event VARCHAR(3)
);

INSERT INTO ext (key, id, pid, sid, oid, event)
VALUES 
 (1, 'Q', 1, 81, 20, 'tsu'),
 (2, 'Q', 1, 81, 9, 'tsu'),
 (3, 'Q', 1, 81, 10, 'tsu'),
 (4, 'Q', 1, 81, 4, 'tsu'),
 (5, 'Q', 1, 81, 15, 'tsu'),
 (6, 'Q', 1, 81, 3, 'tsu'),
 (7, 'Q', 1, 81, 5, 'tsu'),
 (8, 'Q', 1, 81, 18, 'tsu'),
 (9, 'Q', 1, 81, 2, 'tsu'),
 (10, 'Q', 1, 81, 1, 'tsu'),
 (11, 'Q', 1, 81, 7, 'tsu'),
 (12, 'f', 2, 2, NULL, 's'),
 (13, 'Z', 2, 871, NULL, 'e'),
 (14, 'm', 3, 872, 2, 'pof'),
 (15, 's', 3, 873, 31, 'pom'),
 (16, 'R', 3, 874, 15, 'fc'),
 (17, 'R', 3, 874, 1, 'fc'),
 (18, 'R', 3, 874, 31, 'fc'),
 (19, 'R', 3, 874, 9, 'fc'),
 (20, 'R', 3, 874, 10, 'fc'),
 (21, 'R', 3, 874, 4, 'fc'),
 (22, 'R', 3, 874, 7, 'fc'),
 (23, 'R', 3, 874, 3, 'fc'),
 (24, 'R', 3, 874, 5, 'fc'),
 (25, 'R', 3, 874, 18, 'fc'),
 (26, 'R', 3, 874, 20, 'fc'),
 (27, 'k', 3, 876, NULL, 's'),
 (28, 'a', 3, 950, 31, 'rco'),
 (29, 'y', 3, 1285, 7, 'pof'),
 (30, 'N', 3, 1286, 22, 'pom'),
 (31, 'i', 3, 1299, 1, 'fc'),
 (32, 'i', 3, 1299, 5, 'fc'),
 (33, 'i', 3, 1299, 3, 'fc'),
 (34, 'i', 3, 1299, 20, 'fc'),
 (35, 'i', 3, 1299, 4, 'fc'),
 (36, 'i', 3, 1299, 9, 'fc'),
 (37, 'i', 3, 1299, 10, 'fc'),
 (38, 'i', 3, 1299, 22, 'fc'),
 (39, 'i', 3, 1299, 15, 'fc'),
 (40, 'i', 3, 1299, 18, 'fc'),
 (41, 'I', 3, 1407, 9, 'pof'),
 (42, 'T', 3, 1408, 19, 'pom'),
 (43, 'u', 3, 1575, 4, 'pof'),
 (44, 'V', 3, 1576, 30, 'pom'),
 (45, 'B', 3, 2019, NULL, 'e'),
 (46, 'h', 4, 60, NULL, 'e');

事件根据pid 和sid 列进行排序（例如，您可以分别以天和小时的形式查看它们，因为 pid 的时间单位比 sid 大，因此您应该首先按 pid 和然后通过 sid 获得正确的顺序）。如您所见，一些事件（event = tsu 或event = fc）有不止一行，因为它们引用了许多对象（oid），有些只引用了一个对象（如id = m 的事件），并且有些只有一行，但它们实际上指的是所有先前观察到的不是“死”的物体。它们是一些附加规则：

• 对象在遇到pof 或rco 事件时已死亡（如event 列中所述）
• 当对象遇到pof 事件时，会有另一个对象替换它并标记为pom 事件

我需要跟踪当前活动的对象。因此，我想将oid 是NULL 的行与可以从先前事件中推断出的所有活动对象“交叉连接”，其中“交叉连接”是指用oid = NULL 复制该行对于每个当前活跃的oid。

由于可能难以从文本中掌握逻辑，因此我准备了预期的输出（可在SQL fiddle here 获得）：

CREATE TABLE intermediate_result (
  id CHAR(1),
  pid INT,
  sid INT, 
  oid INT,
  event VARCHAR(3)
);

INSERT INTO intermediate_result (id, pid, sid, oid, event)
VALUES 
 ('Q', 1, 81, 20, 'tsu'),
 ('Q', 1, 81, 9, 'tsu'),
 ('Q', 1, 81, 10, 'tsu'),
 ('Q', 1, 81, 4, 'tsu'),
 ('Q', 1, 81, 15, 'tsu'),
 ('Q', 1, 81, 3, 'tsu'),
 ('Q', 1, 81, 5, 'tsu'),
 ('Q', 1, 81, 18, 'tsu'),
 ('Q', 1, 81, 2, 'tsu'),
 ('Q', 1, 81, 1, 'tsu'),
 ('Q', 1, 81, 7, 'tsu'),
 ('f', 2, 2, 20, 's'),
 ('f', 2, 2, 9, 's'),
 ('f', 2, 2, 10, 's'),
 ('f', 2, 2, 4, 's'),
 ('f', 2, 2, 15, 's'),
 ('f', 2, 2, 3, 's'),
 ('f', 2, 2, 5, 's'),
 ('f', 2, 2, 18, 's'),
 ('f', 2, 2, 2, 's'),
 ('f', 2, 2, 1, 's'),
 ('f', 2, 2, 7, 's'),
 ('Z', 2, 871, 20, 'e'), 
 ('Z', 2, 871, 9, 'e'),
 ('Z', 2, 871, 10, 'e'),
 ('Z', 2, 871, 4, 'e'),
 ('Z', 2, 871, 15, 'e'),
 ('Z', 2, 871, 3, 'e'),
 ('Z', 2, 871, 5, 'e'),
 ('Z', 2, 871, 18, 'e'),
 ('Z', 2, 871, 2, 'e'),
 ('Z', 2, 871, 1, 'e'),
 ('Z', 2, 871, 7, 'e'),
 ('m', 3, 872, 2, 'pof'),
 ('s', 3, 873, 31, 'pom'),
 ('R', 3, 874, 15, 'fc'),
 ('R', 3, 874, 1, 'fc'),
 ('R', 3, 874, 31, 'fc'),
 ('R', 3, 874, 9, 'fc'),
 ('R', 3, 874, 10, 'fc'),
 ('R', 3, 874, 4, 'fc'),
 ('R', 3, 874, 7, 'fc'),
 ('R', 3, 874, 3, 'fc'),
 ('R', 3, 874, 5, 'fc'),
 ('R', 3, 874, 18, 'fc'),
 ('R', 3, 874, 20, 'fc'),
 ('k', 3, 876, 15, 's'),
 ('k', 3, 876, 1, 's'),
 ('k', 3, 876, 31, 's'),
 ('k', 3, 876, 9, 's'),
 ('k', 3, 876, 10, 's'),
 ('k', 3, 876, 4, 's'),
 ('k', 3, 876, 7, 's'),
 ('k', 3, 876, 3, 's'),
 ('k', 3, 876, 5, 's'),
 ('k', 3, 876, 18, 's'),
 ('k', 3, 876, 20, 's'),
 ('a', 3, 950, 31, 'rco'),
 ('y', 3, 1285, 7, 'pof'),
 ('N', 3, 1286, 22, 'pom'),
 ('i', 3, 1299, 1, 'fc'),
 ('i', 3, 1299, 5, 'fc'),
 ('i', 3, 1299, 3, 'fc'),
 ('i', 3, 1299, 20, 'fc'),
 ('i', 3, 1299, 4, 'fc'),
 ('i', 3, 1299, 9, 'fc'),
 ('i', 3, 1299, 10, 'fc'),
 ('i', 3, 1299, 22, 'fc'),
 ('i', 3, 1299, 15, 'fc'),
 ('i', 3, 1299, 18, 'fc'),
 ('I', 3, 1407, 9, 'pof'),
 ('T', 3, 1408, 19, 'pom'),
 ('u', 3, 1575, 4, 'pof'),
 ('V', 3, 1576, 30, 'pom'),
 ('B', 3, 2019, 1, 'e'),
 ('B', 3, 2019, 5, 'e'),
 ('B', 3, 2019, 3, 'e'),
 ('B', 3, 2019, 20, 'e'),
 ('B', 3, 2019, 30, 'e'),
 ('B', 3, 2019, 19, 'e'),
 ('B', 3, 2019, 10, 'e'),
 ('B', 3, 2019, 22, 'e'),
 ('B', 3, 2019, 15, 'e'),
 ('B', 3, 2019, 18, 'e'),
 ('h', 4, 60, 1, 'e'),
 ('h', 4, 60, 5, 'e'),
 ('h', 4, 60, 3, 'e'),
 ('h', 4, 60, 20, 'e'),
 ('h', 4, 60, 30, 'e'),
 ('h', 4, 60, 19, 'e'),
 ('h', 4, 60, 10, 'e'),
 ('h', 4, 60, 22, 'e'),
 ('h', 4, 60, 15, 'e'),
 ('h', 4, 60, 18, 'e');

SQL 版本为 PostgreSQL 9.5。

Answer 1

仅使用 SQL 解决这个问题非常困难且效率低下。我认为您最好的选择是程序解决方案。

这是 PL/pgSQL 中的一个实现。

CREATE OR REPLACE FUNCTION f_expand_oid_null()
  RETURNS TABLE(_id CHAR(1), _pid int, _sid int, _oid int, _event varchar(3))
  LANGUAGE plpgsql AS
$func$
DECLARE
   _key   int;
   _pof   int;  -- remember for subsequent 'pom'
BEGIN
   -- hold set of "active object IDs
   CREATE TEMP TABLE tmp_active_objects(
     oid int PRIMARY KEY
   , pid int
   , sid int
   , key int
   ) ON COMMIT DROP;

-- loop table rows in order
   FOR _key, _id, _pid, _sid, _oid, _event IN
      SELECT e.key, e.id, e.pid, e.sid, e.oid, e.event
      FROM   ext e
      ORDER  BY e.pid, e.sid, e.key
   LOOP
      IF _oid IS NULL THEN
         -- expand to ordered set of active objects
         RETURN QUERY
         SELECT _id, _pid, _sid, a.oid, _event 
         FROM   tmp_active_objects a
         ORDER  BY a.pid, a.sid, a.key;  -- keep original order of events
         -- returns nothing if no active objects
      ELSE
         RETURN QUERY VALUES (_id, _pid, _sid, _oid, _event);
         
         CASE _event
         WHEN 'rco' THEN
            DELETE FROM tmp_active_objects WHERE oid = _oid;
         WHEN 'pof' THEN
            _pof = _oid;   -- remember for subsequent 'pom'
         WHEN 'pom' THEN
            UPDATE tmp_active_objects
            SET    oid = _oid
            WHERE  oid = _pof;
         ELSE
            -- upsert active objects
            INSERT INTO tmp_active_objects (oid, pid, sid, key)
            VALUES (_oid, _pid, _sid, _key)
            ON CONFLICT (oid) DO
            UPDATE
            SET    (pid, sid, key)
                 = (EXCLUDED.pid, EXCLUDED.sid, EXCLUDED.key);
         END CASE;
      END IF;
   END LOOP;
END
$func$;

db小提琴here

解释一切比写东西更费力。我做了一些假设和要避免的陷阱。特别是，每个 'pof' 行必须紧跟一个 'pom' 行。

如果您对 PL/pgSQL 不坚定，请考虑聘请付费顾问。或者以您选择的程序语言实现。

Answer 2

我终于能够进入 SQLFiddle 正确地查看问题。

应该重申主请求，说您希望交叉连接具有空值的活动对象，同时保留所有非空 oid 值的行

理解：

1. oid值代表对象
2. 根据结果数据，活动对象依赖于时间，因此要计算活动对象，我们将依赖特定的时间行 ID，它代表时间。
3. 表格插入是与时间相关的，并且将进入未来，后面的行代表未来时间
4. 问题：根据主要请求替换 pom 对象的相关性仍未完全理解，对解决方案没有任何影响。

解决方案：

对于解决方案，有 3 个部分 -

1. 添加到您的分机表的自动递增字段。您已经将其添加为 INT 并将其命名为 Key。这将用作唯一的 TimeID

With DistinctTimeIDs as
(
  select a.key as TimeID from ext a
)

1. 活动对象 - 历史确实很重要。在这种情况下，我们希望在没有 pof 或 rco 事件的特定 TimeID 之前的所有非空 oid。这将为数据集中的每个 TimeID 列出该 TimeID 之前的所有 Active oid。

ActiveObjects as 
( 
  select b.TimeID, a.oid from ext a inner join DistinctTimeIDs b on b.TimeID>=a.key
  where oid is not null 
  and not exists (select 'x' from ext where key<b.TimeID and event in ('pof', 'rco') and oid=a.oid) 
  and a.key = (select MAX(c.key) from ext c where c.key<b.TimeID and c.event not in ('pof', 'rco') and c.oid=a.oid)
)

1. 空对象值行

With NullObjectValues as 
(
  select * from ext a 
  where a.oid is null 
)

综上所述，我们将合并非空对象行和空对象行，并与每个 TimeID 的活动对象交叉连接

With DistinctTimeIDs as
(
  select a.key as TimeID from ext a
), ActiveObjects as 
( 
  select b.TimeID, a.oid from ext a inner join DistinctTimeIDs b on b.TimeID>=a.key
  where oid is not null 
  and not exists (select 'x' from ext where key<b.TimeID and event in ('pof', 'rco') and oid=a.oid) 
  and a.key = (select MAX(c.key) from ext c where c.key<b.TimeID and c.event not in ('pof', 'rco') and c.oid=a.oid)
), NullObjectValues as 
(
  select * from ext a 
  where a.oid is null 
)
select a.key ,a.id,a.pid,a.sid,a.oid,a.event from ext a where a.oid is not null
union all
select a.key ,a.id,a.pid,a.sid,b.oid,a.event from NullObjectValues a CROSS JOIN ActiveObjects b
where b.TimeID = a.key 
order by 1;

SQL 小提琴是http://sqlfiddle.com/#!17/2fb57/2