sql - 查找不连续的用户记录

Question

我无法弄清楚如何启动此查询。

我有一个包含以下列和数据的表格:

User   BeginMile EndMile
1         1        5
1         5        6
1         6        20
1         20       25
1         25       29
2         1         9
2         15        20
3         1         2
3         6         10
3         10        12

我需要首先找到每个用户从上一条记录的 EndMile 到下一条记录的 BeginMile 之间的差距。然后，我需要返回每个用户出现间隙之前和之后的记录。

在前面的数据示例中，我希望返回以下内容:

User   PrevBeginMile   PrevEndMile    AfterBeginMile AfterEndMile   Gap
2         1                9                15          20           6
3         1                2                6           10           4

如何做到这一点？

Answer 1

考虑到您使用的是 SQL 2005，这应该可行:

DECLARE @Runners TABLE (Id INT, BeginMile INT, EndMile INT)

INSERT INTO @Runners VALUES (1,1,5)
INSERT INTO @Runners VALUES (1,5,6)
INSERT INTO @Runners VALUES (1,6,20)
INSERT INTO @Runners VALUES (1,20,25)
INSERT INTO @Runners VALUES (1,25,29)
INSERT INTO @Runners VALUES (2,1,9)
INSERT INTO @Runners VALUES (2,15,20)
INSERT INTO @Runners VALUES (3,1,2)
INSERT INTO @Runners VALUES (3,6,10)
INSERT INTO @Runners VALUES (3,10,12)

WITH OrderedUsers AS (
    SELECT  *
    ,   ROW_NUMBER() OVER (PARTITION BY Id ORDER BY BeginMile) RowNum
    FROM    @Runners
)

SELECT  a.Id [User]
,   a.BeginMile PrevBeginMile
,   a.EndMile PrevEndMile
,   b.BeginMile AfterBeginMile
,   b.EndMile AfterEndMile
,   b.BeginMile - a.EndMile Gap
FROM    OrderedUsers a
JOIN    OrderedUsers b
ON  a.Id = b.Id
AND a.EndMile <> b.BeginMile
AND a.RowNum = b.RowNum - 1