SQL XML path conversion results error - sql

Question

Actually I m begineer to SQL XML path as so making me professional, Got a scenario...
I have a CTE Function That results as
Data Chars NumberOfOccurance
12 1 1 appears (1 ) times
12 2 2 appears (1 ) times
xx x x appears (2 ) times
and CTE function is :
;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
Actually I just want to make my answer into this :
data Number_of_occurances
12 1 appears (1) times 2 appears (1) times
xx x appears (2) times
I have tries this :
; 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
It says :
Column 'Ctea.Chars' is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause.
when I use temp table and getting my exact answer , but cant do it CTE
Can anyone make my result ?

Answer 1

The problem has nothing to do with your CTE. It actually lies in the following subquery:
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('')
Note how you are using the aggregate COUNT(*) here as well as the column Chars. You need to group by at least Chars here:
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('')
Furthermore, you do not want to select or group by t1.Chars in the outer query because it will result in one row per value of Chars:
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
Finally you should most likely be using the STUFF function, and not REPLACE, as you are trying to create a space-delimited list ("1 appears (1) times 2 appears (1) times"), not replace all space characters with a space and a semicolon ("1 ;appears ;(1) ;times ;2 ;appears ;(1) ;times").
Therefore your final query should be:
; 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

Answer 2

You can use FOR XML PATH like this for concatenation
;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