The query processor could not produce a query plan

Question

I'm getting this message:
Msg 8624, Level 16, State 17, Line 1
Internal Query Processor Error: The query processor could not produce a query plan. For more information, contact Customer Support Services.
This is what I run
;WITH TableA AS
SELECT 101 as A_ID
,TableB AS
SELECT 1 as B_ID, 101 as B_A_ID , 'xxx' as B_Courses
UNION ALL
SELECT 2 , 101 , 'YYY'
UNION ALL
SELECT 3 , 101 , 'ZZZ'
UNION ALL
SELECT 4 , 102 , 'AAA'
SELECT
A_id
,x.x.value('(./text())[1]','varchar(500)') AS fieldX
FROM
TableA AS A
OUTER APPLY
-- CROSS APPLY
(SELECT
',' + B_Courses
FROM
TableB AS B
WHERE
1=1
AND B.B_A_ID = A.A_ID
FOR XML PATH(''),TYPE
) x(x)
With OUTER
APPLY, I get the message shown above.
With CROSS
APPLY, everything works nicely.
I resolve by adding in select this :
STUFF((SELECT ','+B_Courses
FROM
TableB AS B
WHERE
B.B_A_ID = A.A_ID
FOR XML PATH(''),TYPE).value('(./text())[1]' ,'VARCHAR(500)'),1,1,'')
Tested on:
Edition ProductVersion ProductLevel
Express Edition 9.00.3042.00 SP2
and
Edition ProductVersion ProductLevel
Developer Edition (64-bit) 11.0.2100.60 RTM
Any idea way is this happening?
Thanks

Answer 1

Is the below working for you?
;WITH TableA AS
SELECT 101 as A_ID
,TableB AS
SELECT 1 as B_ID, 101 as B_A_ID , 'xxx' as B_Courses
UNION ALL
SELECT 2 , 101 , 'YYY'
UNION ALL
SELECT 3 , 101 , 'ZZZ'
UNION ALL
SELECT 4 , 102 , 'AAA'
SELECT
A_id
-- ,x.x.value('(./text())[1]','varchar(500)') AS fieldX --Commented this part
FROM
TableA AS A
OUTER APPLY
-- CROSS APPLY
(SELECT
',' + B_Courses
FROM
TableB AS B
WHERE
1=1
AND B.B_A_ID = A.A_ID
FOR XML PATH(''),TYPE
) x(x)