sql for xml 还有一种写法（採用 tag 与 union all，简洁易懂）
測试环境：sql 08, 08 R2, 2010, 2012, 2014 等
declare @agent table
(
AgentID int,
Fname varchar(5),
SSN varchar(11)
) insert into @agent
select 1, 'Vimal', '123-23-4521' union all
select 2, 'Jacob', '321-52-4562' union all
select 3, 'Tom', '252-52-4563' declare @address table
(
AddressID int,
AddressType varchar(12),
Address1 varchar(20),
Address2 varchar(20),
City varchar(25),
AgentID int
) insert into @address
select 1, 'Home', 'abc', 'xyz road', 'RJ', 1 union all
select 2, 'Office', 'temp', 'ppp road', 'RJ', 1 union all
select 3, 'Home', 'xxx', 'aaa road', 'NY', 2 union all
select 4, 'Office', 'ccc', 'oli Com', 'CL', 2 union all
select 5, 'Temp', 'eee', 'olkiu road', 'CL', 2 union all
select 6, 'Home', 'ttt', 'loik road', 'NY', 3 --SELECT
-- 1 AS Tag,
-- NULL AS Parent,
-- 0 AS 'Agents!1!Sort!hide',
-- NULL AS 'Agents!1!',
-- NULL AS 'Agent!2!AgentID',
-- NULL AS 'Agent!2!Fname!Element',
-- NULL AS 'Agent!2!SSN!Element',
-- NULL AS 'AddressCollection!3!Element',
-- NULL AS 'Address!4!!xml',
-- NULL AS 'Address!4!AddressType!Element',
-- NULL AS 'Address!4!Address1!Element',
-- NULL AS 'Address!4!Address2!Element',
-- NULL AS 'Address!4!City!Element'
--UNION ALL
-- SELECT
-- 2 AS Tag,
-- 1 AS Parent,
-- AgentID * 100,
-- NULL, AgentID, Fname, SSN,
-- NULL, NULL, NULL, NULL, NULL, NULL
--FROM @Agent
--UNION ALL
-- SELECT
-- 3 AS Tag,
-- 2 AS Parent,
-- AgentID * 100 + 1,
-- NULL,NULL,NULL,
-- NULL,
-- NULL,
-- NULL, NULL, NULL, NULL, NULL
--FROM @Agent
--UNION ALL
--SELECT
-- 4 AS Tag,
-- 3 AS Parent,
-- AgentID * 100 + 2,
-- NULL, NULL, NULL, NULL, NULL,
-- '<!-- ' + AddressType + ' Address -->', AddressType,
-- Address1, Address2, City
--FROM @Address
--ORDER BY [Agents!1!Sort!hide]
--FOR XML EXPLICIT SELECT
1 AS Tag,
NULL AS Parent,
NULL AS [Agents!1!],
NULL AS [Agent!2!AgentID],
NULL AS [Agent!2!Fname!Element],
NULL AS [Agent!2!SSN!Element],
NULL AS [AddressCollection!3!Element],
NULL AS [Address!4!AddressType!Element],
NULL AS [Address!4!Address1!Element],
NULL AS [Address!4!Address2!Element],
NULL AS [Address!4!City!Element] UNION ALL SELECT
2 AS Tag,
1 AS Parent,
NULL, AgentID, Fname, SSN,
NULL,NULL, NULL, NULL, NULL
FROM @Agent UNION ALL SELECT
3 AS Tag,
2 AS Parent,
NULL,AgentID,NULL, NULL,
NULL, NULL, NULL, NULL, NULL FROM @Agent UNION ALL SELECT
4 AS Tag,
3 AS Parent,
NULL,AgentID,NULL,NULL,NULL,
AddressType, Address1, Address2, City FROM @Address ORDER BY
-- all properties of every agent
-- (from tag 2 and 4: SSN, fname and adresses)
-- will be sorted by agentID and combined into
-- separate groups. It is necessary in same cases.
[Agent!2!AgentID],
[AddressCollection!3!Element], -- optional because NULL everywhere
[Address!4!AddressType!Element]-- any ordering by elements of tag 4 FOR XML EXPLICIT
执行结果：
文章来源：http://social.msdn.microsoft.com/Forums/sqlserver/zh-CN/97f79941-324e-479e-ba5b-851cc534ebe5/problem-in-for-xml-explicit-query?
forum=sqlxml