将派生表与其自身联接

Question

简而言之：

我有事件表： [tbl]

time | newState
1200 | 1
1300 | 2
1400 | 5

我需要把这个表转换成区间表[intervals]：

t0   | t1   | state
1200 | 1300 | 1
1300 | 1400 | 2

限制：SQL 紧凑版

查询：

SELECT leftPart.time AS t0, min(rightPart.time) AS t1, leftPart.newState
FROM tbl AS leftPart 
LEFT OUTER JOIN tbl As rightPart
ON leftPart.time<rightPart.time
GROUP BY leftPart.Time,leftPart.newState

当 [tbl] 是数据库中的永久表时，它可以完美运行，但在我的情况下，[tbl] 是从另一个选择子查询派生的！像这样：

(SELECT time,newState
from ...) AS derivedTb

所以，当我尝试这样的事情时：

SELECT derivedTbl.time As t0,derivedTbl.state,min(rigthTblPart.time) FROM
(SELECT time,newState
from ...) AS derivedTbl
LEFT OUTER JOIN with derivedTbl AS rigthTblPart
ON derivedTbl.Time<rightTblPart.Time ...

它抛出错误：“derivedTbl 不存在”...

它的别名下的派生表似乎对更高级别的查询不可见（谢谢，谷歌翻译！））...

有没有办法在查询中存储派生表并在查询的不同部分使用它们？ SQL CE 不支持临时表、视图和公用表表达式...

任务详情（如果感兴趣）： 我有 2 个事件表：

[states1]
time | state1
1200 | 1
1300 | 2
1400 | 3

[states2]
time | state2
1200 | 0
1230 | 10
1330 | 20
1430 | 30

我需要将它们转换成区间表：

[intervals]
t0      t1      state1  state2
1200    1230    1   0
1230    1300    1   10
1300    1330    2   10
1330    1400    2   20
1400    1430    3   20
1430    NULL    3   30

转化阶段： 1. 总体时间线

(SELECT Time FROM States1 
UNION
SELECT Time FROM States2) AS timetbl

1. 加入 states1 表
2. 加入 states2 表

目前一切顺利：

SELECT     states12tbl.time, states12tbl.state1, states2tbl.State AS state2
   FROM          (SELECT     states12tbl_1.time, states12tbl_1.state1, MAX(states2tbl.Time) AS states2time
       FROM          (SELECT     timetbl.time, states1tbl.State AS state1
           FROM          (SELECT     timetbl_1.Time AS time, MAX(States1tbl.Time) AS state1time
               FROM          (SELECT     Time
                   FROM          States1
                   UNION
                   SELECT     Time
                   FROM         States2) AS timetbl_1 LEFT OUTER JOIN
                  States1 AS States1tbl ON States1tbl.Time <= timetbl_1.Time
               GROUP BY timetbl_1.Time) AS timetbl INNER JOIN
              States1 AS states1tbl ON timetbl.state1time = states1tbl.Time

1. 自己加入表...这里有问题，我需要自己加入code(3)，因为sql ce无法记住临时表...如果您有更好的想法，请分享:)

Answer 1

根据您的第一个 SELECT 创建一个 VIEW。

Answer 2

Onotole，我认为这个 WITH 很麻烦。

像这样重写这个查询

SELECT 
    derivedTbl.time As t0,
    derivedTbl.state,
    min(rigthTblPart.time) 
FROM
   (SELECT time,newState from ...) AS derivedTbl
   LEFT OUTER JOIN derivedTbl AS rigthTblPart
       ON derivedTbl.Time<rightTblPart.Time 
....