我有一些奇怪的要求,它们要求特定的XML格式。由于截止日期短和缺乏技能,我决定做一个快速的解决方案,通过字符串连接生成XML。
DECLARE @tbl TABLE(personID int identity, name varchar(20), lastname varchar(20), country varchar(20));
INSERT INTO @tbl VALUES
('bob','bobby','USA')
,('mike','mikeson','Canada')
,('jack', 'jackson', 'Mexico')
select '<personID="' + cast(personID as varchar) +'" country="' + country + '"/>' +
'"<FIELD fieldname="name" value="' + name + '"/>' +
'<FIELD fieldname="lastname" value="' + lastname + '"/>' +
'</personID>'
from @tbl
这给出了我需要的输出。但是,我已经无数次被告知这不是最佳实践,因此不鼓励通过字符串连接创建XML。还有其他一些方法可以使用更高级的XML技术来实现相同的结果吗?
--string concat, is it valid xml??
select try_cast('<personID="' + cast(personID as varchar) +'" country="' + country + '"/>' +
'"<FIELD fieldname="name" value="' + name + '"/>' +
'<FIELD fieldname="lastname" value="' + lastname + '"/>' +
'</personID>' as xml)
from @tbl;
--..add null columns
INSERT INTO @tbl VALUES
,(null, null, null)
,(null, 'null name', null)
,('null lastname', null, null);
--exclude fieldname for null columns
select
(
select t.personID as '@ID', t.country as '@country',
case when t.name is not null then 'name' end as 'FIELD/@fieldname',
t.name as 'FIELD/@value',
'',
case when t.lastname is not null then 'lastname' end as 'FIELD/@fieldname', t.lastname as 'FIELD/@value'
for xml path('person'), type
)
from @tbl t
where name is not null or lastname is not null or country is not null;
--A
select
(
select t.personID as '@ID', t.country as '@country',
'name' as 'FIELD/@fieldname', t.name as 'FIELD/@value',
'',
'lastname' as 'FIELD/@fieldname', t.lastname as 'FIELD/@value'
for xml path('person'), type
)
from @tbl t;
--B
select
(
select t.personID as 'person/@ID', t.country as 'person/@country',
'name' as 'person/FIELD/@fieldname', t.name as 'person/FIELD/@value',
'' as 'person',
'lastname' as 'person/FIELD/@fieldname', t.lastname as 'person/FIELD/@value'
for xml path(''), type
)
from @tbl t;
--single xml for the whole table
select t.personID as '@ID', t.country as '@country',
'name' as 'FIELD/@fieldname', t.name as 'FIELD/@value',
'',
'lastname' as 'FIELD/@fieldname', t.lastname as 'FIELD/@value'
from @tbl t
for xml path('person');