XQuery存在檢查中選擇SQL查詢

Question

我有一個帶有xml列的sql表，其中包含類似xml下面的值

<Security xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <Dacl>
    <ACEInformation>
      <UserName>Authenticated Users</UserName>
      <Access>Allow</Access>
      <IsInherited>false</IsInherited>
      <ApplyTo>This object only</ApplyTo>
      <Permission>List Contents</Permission>
      <Permission>Read All Properties</Permission>
      <Permission>Read Permissions</Permission>
    </ACEInformation>
    <ACEInformation>
      <UserName>Administrator</UserName>
      <Access>Allow</Access>
      <IsInherited>false</IsInherited>
      <ApplyTo>This object only</ApplyTo>
      <Permission>Read All Properties</Permission>
      <Permission>Delete</Permission>
    </ACEInformation>
    <ACEInformation>
      <UserName>Admin2</UserName>
      <Access>Allow</Access>
      <IsInherited>false</IsInherited>
      <ApplyTo>This object only</ApplyTo>
      <Permission>Read All Properties</Permission>
      <Permission>Delete</Permission>
    </ACEInformation>
    <ACEInformation>
      <UserName>Admin2</UserName>
      <Access>Deny</Access>
      <IsInherited>false</IsInherited>
      <ApplyTo>This object only</ApplyTo>
      <Permission>Read All Properties</Permission>
      <Permission>Delete</Permission>
    </ACEInformation>
  </Dacl>
</Security>

在這里，我需要查詢所有具有訪問權限：允許和許可權限：刪除的 UserName值。 為此，我正在使用以下XQuery。

select (
       select A.X.value('(UserName/text())[1]', 'nvarchar(max)')+';'
       from T.xmlColumn.nodes('/Security/Dacl/ACEInformation[Access = "Allow" and Permission = "Delete"]') as A(X)
       for xml path(''), type
       ).value('text()[1]', 'nvarchar(max)')
from myTable as T

它返回上述xml值： Administrator; Admin2 。 查詢工作正常。

但是在這里，我希望結果只有一個條目Administrator而不是Admin2 ..因為Admin2在兩個不同的ACEInformation節點中都具有Access：Allow和Access：Deny值。

在那種情況下，即使它具有Access：Allow ，我也必須從結果中排除Admin2 。

有人能給我這種情況下的xquery嗎？

Answer 1

with cte as (
    select
        A.X.value('(UserName/text())[1]', 'nvarchar(max)') as UserName,
        A.X.value('(Access/text())[1]', 'nvarchar(max)') as Access
    from myTable as T
        outer apply T.xmlColumn.nodes('/Security/Dacl/ACEInformation[Permission = "Delete"]') as A(X)
)
select *
from cte as c1
where
    c1.Access = 'Allow' and
    not exists (select * from cte as c2 where c2.UserName = c1.UserName and c2.Access = 'Deny')

sql小提琴演示

更新

這將給您想要的結果。

with cte as (
    select
        T.ID,
        A.X.value('(UserName/text())[1]', 'nvarchar(max)') as UserName,
        A.X.value('(Access/text())[1]', 'nvarchar(max)') as Access
    from myTable as T
        outer apply T.xmlColumn.nodes('/Security/Dacl/ACEInformation[Permission = "Delete"]') as A(X)
)
select
    T.ID,
    stuff(
        (
            select ',' + c1.UserName
            from cte as c1
            where
              c1.ID = T.ID and c1.Access = 'Allow' and
              not exists (select * from cte as c2 where c2.ID = T.ID and c2.UserName = c1.UserName and c2.Access = 'Deny')
            for xml path(''), type
        ).value('.', 'nvarchar(max)')
    ,1,1,'')
from myTable as T

sql小提琴演示

我認為可以使用純XQuery進行此操作，請稍后再添加。