SQL 查询以特定顺序发生的事件

Question

我有以下 table:

+--------+-------+------+--+
| Object | Event | Time |  |
+--------+-------+------+--+
| Obj1   | A     |    1 |  |
| Obj1   | B     |    3 |  |
| Obj2   | A     |    7 |  |
| Obj2   | B     |    4 |  |
+--------+-------+------+--+

我的目标是获取同时具有事件 A 和 B 的所有对象，条件是 A 先发生（及时）。到目前为止，我只是想出查询来查找所有具有 A 和 B 的对象而不包括时间：

SELECT DISTINCT Object 
FROM
    (SELECT * 
     FROM
         (SELECT * 
          FROM table
          INNER JOIN 
              (SELECT Object Obj 
               FROM table 
               WHERE event LIKE '%A%' AS temp_table) ON table.Object = temp_table.Obj) AS temp_final 
     WHERE event LIKE '%B%') AS temp2;

所以最终结果是我得到一个 table，其中仅包含：

Obj1

因为这是唯一满足所有条件的对象。

时间栏是现实生活中的日期戳，但为简单起见，我使用了整数。

感谢您的帮助

Answer 1

这是一个紧凑的解决方案，应该运行跨大多数 RDBMS。此解决方案不假设只有两个事件，并且应该运行用于任意数量的事件。

SELECT t1.Object
FROM yourTable t1
INNER JOIN
(
    SELECT Object, MIN(Time) AS Time
    FROM yourTable
    GROUP BY Object
) t2
    ON t1.Object = t2.Object AND
       ((t1.Event = 'A' AND t1.Time = t2.Time) OR
        t1.Event <> 'A')
GROUP BY t1.Object
HAVING COUNT(*) = 2    -- change this count to match # of events

MySQL 演示：

SQLFiddle

Answer 2

试试这个：

SELECT DISTINCT object
FROM yourtable t
WHERE EXISTS
    (SELECT FROM yourtable t3
    WHERE t3.object = t.object
    AND t3.event = 'A'
    AND EXISTS
        (SELECT 'B'
        FROM yourtbale t4
        WHERE t4.object = t3.object
        AND t4.event = 'B'
        AND t4.time > t3.time)
   )

Answer 3

如果您使用的是sql-服务器：

SELECT
      A.[Object]
    , A.[Time]
    , B.[Time]
FROM
    (SELECT 
        Distinct [Object]
    FROM
        [table] AS A
    WHERE
        A.[Event] = 'A'
    ) AS A
        CROSS APPLY
    (SELECT
        TOP 1 *
    FROM
        [table] AS B
    WHERE
        [Event] = 'B'
        AND
        B.[Object] = A.[Object]
        AND
        A.[Time] < B.[Time]) AS B

Answer 4

如果您只跟踪一个接一个发生的两个事件，那么您可以用一个 JOIN.

来解决这个问题

无论 Obj1 有多少事件，这都会起作用，正如你提到的，你只对 A 和 B 存在并且一个接一个地感兴趣，分别

select distinct t1.object
from TABLE t1
    inner join TABLE t2 on t1.object = t2.object
        and t2.time > t1.time
        and t1.event = 'A'
        and t2.event = 'B'

这是代码结果的示例：

declare @tbl table (obj varchar(10), event varchar(1), time int)

insert @tbl values ('Obj1', 'A', 1), ('Obj1', 'B', 3), ('Obj2', 'A', 7), ('Obj2', 'B', 4)

select distinct t1.obj
from @tbl t1
    inner join @tbl t2 on t1.obj = t2.obj
        and t2.time > t1.time
        and t1.event = 'A'
        and t2.event = 'B'

Answer 5

对于 SQL 服务器：

;with A as
(select Object, MIN(Time) as Time from table where Event='A' group by Object)
, B as
(select Object, MIN(Time) aS Time from table where Event='B' group by Object)
Select A.Object from A inner join B on B.Object=A.Object where A.Time < B.Time

SQL 查询以特定顺序发生的事件

SQL Query for events that happend in a specific order

sql

vertica

SQLFiddle