使用WITH子句的子查询

Question

我有一个表，用于在消息发生时存储消息。通常有一个消息“ A”，有时A被单个消息“ B”分隔。现在，我想对这些值进行分组，以便对它们进行分析，例如查找最长的“ A”条纹或“ A”条纹的分布。查询以黑斑羚编写。

WITH cte as (
SELECT Messages.Message, Timestamp, 
ROW_NUMBER() OVER(PARTITION BY Message ORDER BY Timestamp) AS gn,
ROW_NUMBER() OVER (ORDER BY Timestamp) AS rn
FROM Messages
), cte2 AS (
SELECT Message, Timestamp, gn, rn, gn - rn  as gb
FROM cte 
), cte3 AS (
SELECT Message, MIN(Timestamp) As Ts, COUNT(1) as Cnt
FROM cte2
GROUP BY Message, gb)
SELECT Message, Cnt FROM cte3
ORDER BY Ts

但是当我使用下面的代码时，它的总和为零。

select Message, sum(Cnt ) from (
WITH cte as (
SELECT Messages.Message, Timestamp, 
ROW_NUMBER() OVER(PARTITION BY Message ORDER BY Timestamp) AS gn,
ROW_NUMBER() OVER (ORDER BY Timestamp) AS rn
FROM Messages
), cte2 AS (
SELECT Message, Timestamp, gn, rn, gn - rn  as gb
FROM cte 
), cte3 AS (
SELECT Message, MIN(Timestamp) As Ts, COUNT(1) as Cnt
FROM cte2
GROUP BY Message, gb)
SELECT Message, Cnt FROM cte3
ORDER BY Ts) 
group by Message

即使将上面的代码放在另一个select语句中，它的计数也为零。

select * from (WITH cte as (
SELECT Messages.Message, Timestamp, 
ROW_NUMBER() OVER(PARTITION BY Message ORDER BY Timestamp) AS gn,
ROW_NUMBER() OVER (ORDER BY Timestamp) AS rn
FROM Messages
), cte2 AS (
SELECT Message, Timestamp, gn, rn, gn - rn  as gb
FROM cte 
), cte3 AS (
SELECT Message, MIN(Timestamp) As Ts, COUNT(1) as Cnt
FROM cte2
GROUP BY Message, gb)
SELECT Message, Cnt FROM cte3
ORDER BY Ts ) aa where message='A' 

能帮我找出这里的问题吗？