类似于最近发布的“ t-sql顺序持续时间”，但不完全相同，我想根据x列（在我的情况下为“ who”列）的更改来重置行号。] >
这是第一个返回少量原始数据的查询：
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DISTINCT字，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下一步是我的工作：目标是在“谁”列中的每次值更改时将RowID重置为1。下面的代码获得“几乎在那里”的结果（应该注意的是，我从某个地方偷了/借了这个代码，但现在找不到网站了：）
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.)所需结果：
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感谢您的协助。
类似于最近发布的“ t-sql顺序持续时间””，但不完全相同，我想根据x列（在本例中为“ who”列）的更改来重置行号。这是第一个...
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，并且可以使用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
我通过使用Rank（）成功解决了此问题：
而不是：
我能想到的唯一解决方案是使用游标（ugh）并经历RBAR过程。这不是一个很好的解决方案，因为游标必须读取超过1m的行。闷闷不乐。