从SQL Server 2008中的XML字段中select值
只要看看我的XML字段，我的行看起来像这样：
<person><firstName>Jon</firstName><lastName>Johnson</lastName></person> <person><firstName>Kathy</firstName><lastName>Carter</lastName></person> <person><firstName>Bob</firstName><lastName>Burns</lastName></person> 请注意，这是我的表中的三行。
我想返回一个SQL结果作为一个表中
Jon | Johnson Kathy| Carter Bob | Burns
什么查询将完成此？
鉴于XML字段被命名为“xmlField”…
SELECT [xmlField].value('(/person//firstName/node())[1]', 'nvarchar(max)') as FirstName, [xmlField].value('(/person//lastName/node())[1]', 'nvarchar(max)') as LastName FROM [myTable]
考虑到XML数据来自表'table'并存储在'field'列中：使用XML方法 ，使用xml.value()提取值，使用xml.value()提取项目节点，使用CROSS APPLY来join：
SELECT p.value('(./firstName)[1]', 'VARCHAR(8000)') AS firstName, p.value('(./lastName)[1]', 'VARCHAR(8000)') AS lastName FROM table CROSS APPLY field.nodes('/person') t(p)
如果每个字段只包含一个元素“person”，则可以将nodes() cross apply并cross apply 。 如果XML是variables，则selectFROM @variable.nodes(...) ，而不需要cross apply 。
这篇文章有助于解决我的问题，它有一个不同的XML格式…我的XML包含像下面的示例中的键的列表，我将XML存储在名为DeleteBatch的表中的SourceKeys列中：
<k>1</k> <k>2</k> <k>3</k>
创build表并使用一些数据填充它：
CREATE TABLE dbo.DeleteBatch ( ExecutionKey INT PRIMARY KEY, SourceKeys XML) INSERT INTO dbo.DeleteBatch ( ExecutionKey, SourceKeys ) SELECT 1, (CAST('<k>1</k><k>2</k><k>3</k>' AS XML)) INSERT INTO dbo.DeleteBatch ( ExecutionKey, SourceKeys ) SELECT 2, (CAST('<k>100</k><k>101</k>' AS XML))
这里是我的SQL从XML中select密钥：
SELECT ExecutionKey, p.value('.', 'int') AS [Key] FROM dbo.DeleteBatch CROSS APPLY SourceKeys.nodes('/k') t(p)
这里是查询结果…
ExecutionKey密钥 1 1 1 2 1 3 2 100 2 101
这可能会回答你的问题：
select cast(xmlField as xml) xmlField into tmp from ( select '<person><firstName>Jon</firstName><lastName>Johnson</lastName></person>' xmlField union select '<person><firstName>Kathy</firstName><lastName>Carter</lastName></person>' union select '<person><firstName>Bob</firstName><lastName>Burns</lastName></person>' ) tb SELECT xmlField.value('(person/firstName)[1]', 'nvarchar(max)') as FirstName ,xmlField.value('(person/lastName)[1]', 'nvarchar(max)') as LastName FROM tmp drop table tmp
啊呀。 这是一个非常有用的线程发现。
我仍然发现这些build议中有些令人困惑。 每当我在string中使用[1] value ，它只会检索第一个值。 一些build议使用cross apply （在我的testing）只是带回了太多的数据。
所以，下面是我如何创build一个xml对象的简单示例，然后将其值读入表中。
DECLARE @str nvarchar(2000) SET @str = '' SET @str = @str + '<users>' SET @str = @str + ' <user>' SET @str = @str + ' <firstName>Mike</firstName>' SET @str = @str + ' <lastName>Gledhill</lastName>' SET @str = @str + ' <age>31</age>' SET @str = @str + ' </user>' SET @str = @str + ' <user>' SET @str = @str + ' <firstName>Mark</firstName>' SET @str = @str + ' <lastName>Stevens</lastName>' SET @str = @str + ' <age>42</age>' SET @str = @str + ' </user>' SET @str = @str + ' <user>' SET @str = @str + ' <firstName>Sarah</firstName>' SET @str = @str + ' <lastName>Brown</lastName>' SET @str = @str + ' <age>23</age>' SET @str = @str + ' </user>' SET @str = @str + '</users>' DECLARE @xml xml SELECT @xml = CAST(CAST(@str AS VARBINARY(MAX)) AS XML) -- Iterate through each of the "users\user" records in our XML SELECT x.Rec.query('./firstName').value('.', 'nvarchar(2000)') AS 'FirstName', x.Rec.query('./lastName').value('.', 'nvarchar(2000)') AS 'LastName', x.Rec.query('./age').value('.', 'int') AS 'Age' FROM @xml.nodes('/users/user') as x(Rec)
这里是输出：
这是奇怪的语法，但有一个体面的例子，很容易添加到自己的SQL Serverfunction。
说到这一点，这是对这个问题的正确答案。
假设你的xml数据是xmltypes的@xmlvariables（如我上面的示例中所示），下面是如何从问题中引用的xml中返回三行数据：
SELECT x.Rec.query('./firstName').value('.', 'nvarchar(2000)') AS 'FirstName', x.Rec.query('./lastName').value('.', 'nvarchar(2000)') AS 'LastName' FROM @xml.nodes('/person') as x(Rec)
SELECT cast(xmlField as xml).value('(/person//firstName/node())[1]', 'nvarchar(max)') as FirstName, cast(xmlField as xml).value('(/person//lastName/node())[1]', 'nvarchar(max)') as LastName FROM [myTable]
如果你能够把你的XML包装在一个根元素中 – 比方说下面是你的解决scheme：
DECLARE @PersonsXml XML = '<persons><person><firstName>Jon</firstName><lastName>Johnson</lastName></person> <person><firstName>Kathy</firstName><lastName>Carter</lastName></person> <person><firstName>Bob</firstName><lastName>Burns</lastName></person></persons>' SELECT b.value('(./firstName/text())[1]','nvarchar(max)') as FirstName, b.value('(./lastName/text())[1]','nvarchar(max)') as LastName FROM @PersonsXml.nodes('/persons/person') AS a(b)
/ *这个例子使用一个XMLvariables和模式* /
IF EXISTS (SELECT * FROM sys.xml_schema_collections WHERE name = 'OrderingAfternoonTea') BEGIN DROP XML SCHEMA COLLECTION dbo.OrderingAfternoonTea END GO CREATE XML SCHEMA COLLECTION dbo.OrderingAfternoonTea AS N'<?xml version="1.0" encoding="UTF-16" ?> <xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema" targetNamespace="http://Tfor2.com/schemas/actions/orderAfternoonTea" xmlns="http://Tfor2.com/schemas/actions/orderAfternoonTea" xmlns:TFor2="http://Tfor2.com/schemas/actions/orderAfternoonTea" elementFormDefault="qualified" version="0.10" > <xsd:complexType name="AfternoonTeaOrderType"> <xsd:sequence> <xsd:element name="potsOfTea" type="xsd:int"/> <xsd:element name="cakes" type="xsd:int"/> <xsd:element name="fruitedSconesWithCream" type="xsd:int"/> <xsd:element name="jams" type="xsd:string"/> </xsd:sequence> <xsd:attribute name="schemaVersion" type="xsd:long" use="required"/> </xsd:complexType> <xsd:element name="afternoonTeaOrder" type="TFor2:AfternoonTeaOrderType"/> </xsd:schema>' ; GO DECLARE @potsOfTea int; DECLARE @cakes int; DECLARE @fruitedSconesWithCream int; DECLARE @jams nvarchar(128); DECLARE @RequestMsg NVARCHAR(2048); DECLARE @RequestXml XML(dbo.OrderingAfternoonTea); set @potsOfTea = 5; set @cakes = 7; set @fruitedSconesWithCream = 25; set @jams = N'medlar jelly, quince and mulberry'; SELECT @RequestMsg = N'<?xml version="1.0" encoding="utf-16" ?> <TFor2:afternoonTeaOrder schemaVersion="10" xmlns:TFor2="http://Tfor2.com/schemas/actions/orderAfternoonTea"> <TFor2:potsOfTea>' + CAST(@potsOfTea as NVARCHAR(20)) + '</TFor2:potsOfTea> <TFor2:cakes>' + CAST(@cakes as NVARCHAR(20)) + '</TFor2:cakes> <TFor2:fruitedSconesWithCream>' + CAST(@fruitedSconesWithCream as NVARCHAR(20)) + '</TFor2:fruitedSconesWithCream> <TFor2:jams>' + @jams + '</TFor2:jams> </TFor2:afternoonTeaOrder>'; SELECT @RequestXml = CAST(CAST(@RequestMsg AS VARBINARY(MAX)) AS XML) ; with xmlnamespaces('http://Tfor2.com/schemas/actions/orderAfternoonTea' as tea) select cast( x.Rec.value('.[1]/@schemaVersion','nvarchar(20)') as bigint ) as schemaVersion, cast( x.Rec.query('./tea:potsOfTea') .value('.','nvarchar(20)') as bigint ) as potsOfTea, cast( x.Rec.query('./tea:cakes') .value('.','nvarchar(20)') as bigint ) as cakes, cast( x.Rec.query('./tea:fruitedSconesWithCream') .value('.','nvarchar(20)') as bigint ) as fruitedSconesWithCream, x.Rec.query('./tea:jams').value('.','nvarchar(50)') as jams from @RequestXml.nodes('/tea:afternoonTeaOrder') as x(Rec); select @RequestXml.query('/*')
