获取升序级联排

Question

可能重复：
SQL Server: Can I Comma Delimit Multiple Rows Into One Column?

脚本： -

CREATE TABLE Category (
    ID int, 
    ErrorMessage nvarchar(200) 
) 


INSERT INTO Category 
    (ID, ErrorMessage) 
VALUES 
    (1, 'efgh') 

INSERT INTO Category 
    (ID, ErrorMessage) 
VALUES 
    (1, 'abcd') 

INSERT INTO Category 
    (ID, ErrorMessage) 
VALUES 
    (1, 'ijkl') 

INSERT INTO Category 
    (ID, ErrorMessage) 
VALUES 
    (2, 'efgh') 

INSERT INTO Category 
    (ID, ErrorMessage) 
VALUES 
    (2, 'abcd') 

INSERT INTO Category 
    (ID, ErrorMessage) 
VALUES 
    (2, 'ijkl') 

预计输出

Id     ErrorMessage 
---------------------------------- 
1     abcd,efgh,ijkl 
2     abcd,efgh,ijkl 

请注意，类别ID是分组的，用逗号分隔的消息按升序排列。

Answer 1

Select C.Id 
    , Stuff(
     (
     Select ', ' + C1.ErrorMessage 
     From Category As C1 
     Where C1.Id = C.Id 
     Order By C1.ErrorMessage 
     For Xml Path('') 
     ), 1, 2, '') As Categories 
From Category As C 
Group By C.Id 

Answer 2

select A.ID, STUFF((
    select ','+B.ErrorMessage 
    from Category B 
    where B.ID = A.ID 
    order by B.ErrorMessage 
    for xml path ('a'), type).value('.','nvarchar(max)'),1,1,'') 
from Category A 
group by A.ID 
order by A.ID