Question

我现在已经挣扎了整整三天，我无法理解这一点。它与我最近发表的“t-sql sequential duration”相似，但不完全一样......我想根据列x的变化重置行号（在我的例子中，列“who”）...

这是第一个返回原始（ish）数据的小样本的查询：

SELECT      DISTINCT chr.custno, 
            CAST(LEFT(CONVERT( VARCHAR(20),chr.moddate,112),10)+ ' ' + chr.modtime AS DATETIME)as  moddate, 
            chr.who     
FROM        <TABLE> chr 
WHERE       chr.custno = 581827
            AND LEFT(chr.who, 5) = 'EMSZC'
            AND chr.[description] NOT LIKE 'Recalled and viewed this customer'
ORDER BY    chr.custno

结果：

custno      moddate             who
581827      2012-11-08 08:38:00.000     EMSZC14
581827      2012-11-08 08:41:10.000     EMSZC14
581827      2012-11-08 08:53:46.000     EMSZC14
581827      2012-11-08 08:57:04.000     EMSZC14
581827      2012-11-08 08:58:35.000     EMSZC14
581827      2012-11-08 08:59:13.000     EMSZC14
581827      2012-11-08 09:00:06.000     EMSZC14
581827      2012-11-08 09:04:39.000     EMSZC49 Reset row number to 1
581827      2012-11-08 09:05:04.000     EMSZC49
581827      2012-11-08 09:06:32.000     EMSZC49
581827      2012-11-08 09:12:03.000     EMSZC49
581827      2012-11-08 09:12:38.000     EMSZC49
581827      2012-11-08 09:14:18.000     EMSZC49
581827      2012-11-08 09:17:35.000     EMSZC14 Reset row number to 1

第二步是添加行号（由于使用了单词DISTINCT，我在第一个查询中没有这样做）;所以...

WITH c1 AS (
        SELECT      DISTINCT chr.custno
                    CAST(LEFT(CONVERT( VARCHAR(20),chr.moddate,112),10)+ ' ' + chr.modtime AS DATETIME)as moddate,
                    chr.who
        FROM        <TABLE> chr 
        WHERE       chr.custno = 581827
                    AND LEFT(chr.who, 5) = 'EMSZC'
                    AND chr.[description] NOT LIKE 'Recalled and viewed this customer'
        )

SELECT  ROW_NUMBER() OVER (PARTITION BY custno ORDER BY custno, moddate, who) AS RowID, custno, moddate, who
FROM    c1

结果：

RowID   custno      moddate                      who
1       581827      2012-11-08 08:38:00.000     EMSZC14
2       581827      2012-11-08 08:41:10.000     EMSZC14
3       581827      2012-11-08 08:53:46.000     EMSZC14
4       581827      2012-11-08 08:57:04.000     EMSZC14
5       581827      2012-11-08 08:58:35.000     EMSZC14
6       581827      2012-11-08 08:59:13.000     EMSZC14
7       581827      2012-11-08 09:00:06.000     EMSZC14
8       581827      2012-11-08 09:04:39.000     EMSZC49 Reset row number to 1
9       581827      2012-11-08 09:05:04.000     EMSZC49
10      581827      2012-11-08 09:06:32.000     EMSZC49
11      581827      2012-11-08 09:12:03.000     EMSZC49
12      581827      2012-11-08 09:12:38.000     EMSZC49
13      581827      2012-11-08 09:14:18.000     EMSZC49
14      581827      2012-11-08 09:17:35.000     EMSZC14 Reset row number to 1

下一步是我陷入困境：目标是在“who”列中每次更改值时将RowID重置为1。下面的代码获得了“几乎存在”的结果（应该注意我从某个地方窃取/借用了这段代码，但现在我找不到该网站）：

WITH c1 AS (
        SELECT      DISTINCT chr.custno,
                    CAST(LEFT(CONVERT( VARCHAR(20),chr.moddate,112),10)+ ' ' + chr.modtime AS DATETIME)as moddate,
                    chr.who
        FROM        <TABLE> chr 
        WHERE       chr.custno = 581827
                    AND LEFT(chr.who, 5) = 'EMSZC'
                    AND chr.[description] NOT LIKE 'Recalled and viewed this customer'
        )
, c1a AS    (
            SELECT  ROW_NUMBER() OVER (PARTITION BY custno ORDER BY custno, moddate, who) AS RowID, custno, moddate, who
            FROM    c1
            )

SELECT  x.RowID - y.MinID + 1 AS Row,
        x.custno, x.Touch, x.moddate, x.who      
FROM    (
            SELECT  custno, who, MIN(RowID) AS MinID
            FROM    c1a
            GROUP BY custno, who
        ) AS y
        INNER JOIN c1a x ON x.custno = y.custno AND x.who = y.who

结果：

Row custno      moddate                    who
1   581827      2012-11-08 08:38:00.000     EMSZC14
2   581827      2012-11-08 08:41:10.000     EMSZC14
3   581827      2012-11-08 08:53:46.000     EMSZC14
4   581827      2012-11-08 08:57:04.000     EMSZC14
5   581827      2012-11-08 08:58:35.000     EMSZC14
6   581827      2012-11-08 08:59:13.000     EMSZC14
7   581827      2012-11-08 09:00:06.000     EMSZC14
1   581827      2012-11-08 09:04:39.000     EMSZC49 Reset row number to 1 (Hooray! It worked!)
2   581827      2012-11-08 09:05:04.000     EMSZC49
3   581827      2012-11-08 09:06:32.000     EMSZC49
4   581827      2012-11-08 09:12:03.000     EMSZC49
5   581827      2012-11-08 09:12:38.000     EMSZC49
6   581827      2012-11-08 09:14:18.000     EMSZC49
14  581827      2012-11-08 09:17:35.000     EMSZC14 Reset row number to 1 (Crappies.)

渴望的结果：

Row custno      moddate                     who
1   581827      2012-11-08 08:38:00.000     EMSZC14
2   581827      2012-11-08 08:41:10.000     EMSZC14
3   581827      2012-11-08 08:53:46.000     EMSZC14
4   581827      2012-11-08 08:57:04.000     EMSZC14
5   581827      2012-11-08 08:58:35.000     EMSZC14
6   581827      2012-11-08 08:59:13.000     EMSZC14
7   581827      2012-11-08 09:00:06.000     EMSZC14
1   581827      2012-11-08 09:04:39.000     EMSZC49 Reset row number to 1 
2   581827      2012-11-08 09:05:04.000     EMSZC49
3   581827      2012-11-08 09:06:32.000     EMSZC49
4   581827      2012-11-08 09:12:03.000     EMSZC49
5   581827      2012-11-08 09:12:38.000     EMSZC49
6   581827      2012-11-08 09:14:18.000     EMSZC49
1   581827      2012-11-08 09:17:35.000     EMSZC14 Reset row number to 1

感谢任何帮助。你也可以傻笑我，因为我确信这很容易解决 - 我似乎无法摆脱我自己的方式。

感谢。

Answer 1

如果您使用的是SQL Server 2012，则可以使用LAG将值与上一行进行比较，然后使用SUM和OVER来记录更改。

with C1 as
(
  select custno,
         moddate,
         who,
         lag(who) over(order by moddate) as lag_who
  from chr
),
C2 as
(
  select custno,
         moddate,
         who,
         sum(case when who = lag_who then 0 else 1 end) 
            over(order by moddate rows unbounded preceding) as change 
  from C1
)
select row_number() over(partition by change order by moddate) as RowID,
       custno,
       moddate,
       who
from C2

SQL Fiddle

<强>更新

SQL Server 2005的一个版本。它使用递归CTE和临时表来中间存储您需要迭代的数据。

create table #tmp
(
  id int primary key,
  custno int not null,
  moddate datetime not null,
  who varchar(10) not null
);

insert into #tmp(id, custno, moddate, who)
select row_number() over(order by moddate),
       custno,
       moddate,
       who
from chr;

with C as
(
  select 1 as rowid,
         T.id,
         T.custno,
         T.moddate,
         T.who,
         cast(null as varchar(10)) as lag_who
  from #tmp as T
  where T.id = 1
  union all
  select case when T.who = C.who then C.rowid + 1 else 1 end,
         T.id,
         T.custno,
         T.moddate,
         T.who,
         C.who
  from #tmp as T
    inner join C
      on T.id = C.id + 1
)
select rowid,
       custno,
       moddate,
       who
from C
option (maxrecursion 0);

drop table #tmp;

SQL Fiddle

Answer 2

我使用Rank（）：

成功解决了这个问题

SELECT RANK() OVER (PARTITION BY who ORDER BY custno, moddate) AS RANK

这会返回您想要的结果。我实际上发现这篇文章试图解决同样的问题。

Answer 3

而不是：

PARTITION BY custno ORDER BY custno, moddate, who)

尝试：

PARTITION BY custno, who ORDER BY custno, moddate)

Answer 4

我能想到的唯一解决方案是使用游标（ugh）并通过RBAR过程受到影响。不是一个优雅的解决方案，因为光标必须读取超过1米的行。长号。

T-sql重置字段更改时的行号

4 个答案: