Question

我有XML列，如下所示

<XMLDoc>
    <AAA>
      <Name>Name_A</Name>
      <Value>Val_A</Value>
      <dateReported>1/1/2001<dateReported>
    </AAA>
    <AAA>
      <Name>Name_B</Name>
      <Value>Val_B</Value>
      <dateReported>1/1/2014<dateReported>
    </AAA>
    <AAA>
      <Name>Name_C</Name>
      <Value>Val_C</Value>
      <dateReported>1/1/2012<dateReported>
    </AAA>
    <AAA>
      <Name>Name_D</Name>
      <Value>Val_D</Value>
      <dateReported>1/1/2011<dateReported>
    </AAA></x>
    <BB><ID>12</ID><BB>
    <CC><Type>XML</Type></CC>
</XMLDoc>

我需要获取最大dateReported的名称和值节点。到目前为止，我的sQL如下所示

SELECT 
   Col1 =  Col.value('(/XMLDoc/x/AAA/Name)[1]', 'varchar(255)'),
   Col2 =  Col.value('(/XMLDoc/x/AAA/Value)[2]', 'varchar(255)'),
   Col3 = Col.value('(/XMLDoc/BB/ID)[1]', 'varchar(255)'),
   Col4 = Col.value('(/XMLDoc/CC/Type)[1]', 'varchar(255)')
FROM 
   table t

基本上我需要输出为Name_B，Val_B，12，XML，因为AAA的datereported具有最大值。

Answer 1

你可以尝试这样的事情 - 设置一个CTE（公用表表达式）来提取＆＃34;提取＆＃34;将XML值转换为关系格式，然后对该结果集执行简单的SELECT：

;WITH XmlCTE AS 
(
    SELECT
        ID,
        Name = XC.value('(Name)[1]', 'varchar(100)'),
        Value = XC.value('(Value)[1]', 'varchar(100)'),
        DateReported = XC.value('(dateReported)[1]', 'datetime')
        BB_ID = YourXmlColumn.value('(/XMLDoc/BB/ID)[1]', 'int'), 
        CC_Type = YourXmlColumn.value('(/XMLDoc/CC/Type)[1]', 'varchar(50)')
    FROM
        dbo.YourTable 
    CROSS APPLY
        YourXmlColumn.nodes('/XMLDoc/AAA') AS XT(XC)
)
SELECT *
FROM XmlCTE
WHERE DateReported = (SELECT MAX(DateReported) FROM XmlCTE)

Answer 2

在这种情况下可以使用SQL XML query

with cte as (
SELECT
    t.id,
    name.value('.','nvarchar(50)') as names,
    dates.value('.','nvarchar(50)') as dates
FROM t
CROSS APPLY Col.nodes('/XMLDoc/AAA') as XMLtable1(AAA)
CROSS APPLY XMLtable1.AAA.nodes('Name') as XMLtable2(name)
CROSS APPLY XMLtable1.AAA.nodes('dateReported') as XMLtable3(dates)
)
select * 
from (
select
    *,
    rn = ROW_NUMBER() over (partition by id order by dates desc)
from cte
) t where rn = 1

Answer 3

对于更新后的要求，以下SQL Server XML query可以提供帮助请测试表中多行的查询，以获得更准确的测试结果

;with cte as (
SELECT
    t.id,
    b.value('.','nvarchar(500)') as bbid,
    c.value('.','nvarchar(500)') as cc,
    name.value('.','nvarchar(50)') as names,
    dates.value('.','nvarchar(50)') as dates
FROM t
CROSS APPLY Col.nodes('/XMLDoc/BB/ID') as XMLtable4(b)
CROSS APPLY Col.nodes('/XMLDoc/CC') as XMLtable5(c)
CROSS APPLY Col.nodes('/XMLDoc/x') as XMLtable0(d)
CROSS APPLY XMLtable0.d.nodes('AAA') as XMLtable1(AAA)
CROSS APPLY XMLtable1.AAA.nodes('Name') as XMLtable2(name)
CROSS APPLY XMLtable1.AAA.nodes('dateReported') as XMLtable3(dates)
)
select * 
from (
select
    *,
    rn = ROW_NUMBER() over (partition by id order by dates desc)
from cte
) t where rn = 1

SQL XML Column过滤器基于XML节点聚合函数

3 个答案: