errore CTE: "Tipi non corrispondono tra l'ancoraggio e la parte ricorsiva"

Question

sto eseguendo la seguente dichiarazione:

;WITH cte AS (
    SELECT 
    1 as rn, 
    'name1' as nm 
    UNION ALL 
    SELECT 
    rn + 1, 
    nm = 'name' + CAST((rn + 1) as varchar(255)) 
    FROM cte a WHERE rn < 10) 
SELECT * 
FROM cte 

... che si conclude con l'errore ...

Msg 240, Level 16, State 1, Line 2 
Types don't match between the anchor and the recursive part in column "nm" of recursive query "cte". 

Dove sto facendo l'errore?

Answer 1

esattamente ciò che dice:

'name1' ha un diverso tipo di dati per 'name' + CAST((rn+1) as varchar(255))

Prova questo (non testato)

;with cte as 
(
select 1 as rn, CAST('name1' as varchar(259)) as nm 
union all 
select rn+1,nm = 'name' + CAST((rn+1) as varchar(255)) 
from cte a where rn<10) 
select * from cte 

In sostanza, è necessario garantire la lunghezza corrisponde troppo. Per il bit ricorsivo, potrebbe essere necessario utilizzare CAST('name' AS varchar(4)) se non riesce ancora una volta

Answer 2

è necessario lanciare sia nm campi

;with cte as 
(
select 1 as rn, 
     CAST('name1' AS VARCHAR(255)) as nm 
union all 
select rn+1, 
     nm = CAST('name' + CAST((rn+1) as varchar(255)) AS VARCHAR(255)) 
from cte a where rn<10) 
select * from cte 

Answer 3

;with cte as 
(
select 1 as rn, 'name' + CAST(1 as varchar(255)) as nm 
union all 
select rn+1,nm = 'name' + CAST((rn+1) as varchar(255)) 
from cte a where rn<10) 
select * from cte 

Answer 4

;with tmp1(NewsId,DataItem ,HeaderText) 
as 
    (

    select NewsId, LEFT(HeaderText, CHARINDEX(',',HeaderText+',')-1), 
    STUFF(HeaderText, 1, CHARINDEX(',',HeaderText+','), '') 
    from Currentnews 

    union all 

    select NewsId, LEFT(HeaderText, CHARINDEX(',',HeaderText+',')-1), 
    STUFF(HeaderText, 1, CHARINDEX(',',HeaderText+','), '') 
    from tmp1 
    where HeaderText > '' 

    ) 

    select NewsId, DataItem 
    from tmp1 
    order by NewsId