SQL XML路径转换结果错误

Question

其实我米begineer到SQL XML路径，以便使我的专业，有一个场景...... 我有一个CTE功能结果

Data Chars NumberOfOccurance 
12 1 1 appears (1) times 
12 2 2 appears (1) times 
xx x x appears (2) times 

和CTE功能是：

;with cte as 
    (
     select Data , SUBSTRING(Data,1,1) as Chars,1 as startpos from @t 
     union all 
     select Data, SUBSTRING(Data, startpos+1,1) as char,startpos+1 from cte where startpos+1<=LEN(data) 
    ) 
    select Data,Chars,Cast(Chars as varchar(1)) + ' appears (' + cast(COUNT(*) as varchar(5))+ ') times' as 'NumberOfOccurance' from cte 
    group by data, chars 

其实我只想让我的回答这个：

data Number_of_occurances 
12 1 appears (1) times 2 appears (1) times 
xx x appears (2) times 

我公顷已经尝试这样的：

; With Ctea as 
(
select Data , SUBSTRING(Data,1,1) as Chars,1 as startpos from @t 
    union all 
    select Data, SUBSTRING(Data, startpos+1,1) as char,startpos+1 from ctea where startpos+1<=LEN(data) 
) 
select Data,Chars,REPLACE((SELECT (Cast(Chars as varchar(1)) + ' appears (' + cast(COUNT(*) as varchar(5))+ ') times') AS [data()] FROM Ctea t2 WHERE t2.Data = t1.data FOR XML PATH('')), ' ', ' ;') As Number_of_occurances from ctea as t1 
group by t1.data, t1.Chars 

它说：

Column 'Ctea.Chars' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause. 

当我使用临时表，并让我确切的答案，但不能做它CTE

谁能让我的结果？

Answer 1

您可以使用FOR XML PATH这样的级联

;with cte as 
    (
     select Data , SUBSTRING(Data,1,1) as Chars,1 as startpos from @t 
     union all 
     select Data, SUBSTRING(Data, startpos+1,1) as char,startpos+1 from cte where startpos+1<=LEN(data) 
    ), CTE2 AS 
    (
    select Data,Chars,Cast(Chars as varchar(1)) + ' appears (' + cast(COUNT(*) as varchar(5))+ ') times' as 'NumberOfOccurance' from cte 
    group by data, chars 
    ) 
    SELECT Data,(SELECT NumberOfOccurance + ' ' FROM CTE2 c2 WHERE c2.Data = C1.Data FOR XML PATH(''),type).value('.','VARCHAR(MAX)') as Number_of_occurances 
    FROM CTE2 C1 
    GROUP BY Data 

Answer 2

的问题无关，与你的CTE。实际上，它主要表现在以下子查询：

SELECT (Cast(Chars as varchar(1)) + 
    ' appears (' + 
    cast(COUNT(*) as varchar(5)) + 
    ') times') AS [data()] 
FROM Ctea t2 
WHERE t2.Data = t1.data 
FOR XML PATH('') 

注意你是如何在这里使用聚合COUNT(*)以及列Chars。您需要按至少Chars这里：

SELECT (Cast(Chars as varchar(1)) + 
    ' appears (' + 
    cast(COUNT(*) as varchar(5)) + 
    ') times') AS [data()] 
FROM Ctea t2 
WHERE t2.Data = t1.data 
GROUP BY t2.Chars 
FOR XML PATH('') 

此外，你不想t1.Chars外部查询选择或组，因为它会导致每个字符数的值一行：

 
data chars Number_of_occurances 
12 1  1 appears (1) times 2 appears (1) times 
12 2  1 appears (1) times 2 appears (1) times 
xx x  x appears (2) times 

最后，你应该最有可能被使用STUFF function，而不是REPLACE，因为你正试图创造一个空间分隔的列表（“1出现（1）次2次出现（1）次”），而不是取代所有的空间带有空格和分号的字符（“1;出现;（1）;次数; 2;出现;（1）;次数”）。

所以你最终的查询应该是：

; With Ctea as 
(
    select Data , SUBSTRING(Data,1,1) as Chars,1 as startpos from @t 
    union all 
    select Data, SUBSTRING(Data, startpos+1,1) as char,startpos+1 from ctea 
    where startpos+1<=LEN(data) 
) 
select Data, 
    STUFF((SELECT cast(' ' as varchar(max)) + (Cast(Chars as varchar(1)) + ' appears (' + cast(COUNT(*) as varchar(5))+ ') times') AS [data()] 
      FROM Ctea t2 
      WHERE t2.Data = t1.data 
      GROUP BY t2.Chars 
      FOR XML PATH('')), 1, 1, '') As Number_of_occurances 
from ctea as t1 
group by t1.data