Question

我正在尝试读取xml并将其存储在SQL server中。

DECLARE @xml XML
SET @xml = 
 '<report>
    <personal>
       <search>
           <subject>
               <name>SearchName</name>
           </subject>
       </search>    
    </personal>
    <personal>
       <search>
           <subject>
               <name>SearchName</name>
           </subject>
       </search>
       <result>
           <history>
              <name>HistoryName</name>
           </history>
       </result>
    </personal>
    <personal>
       <search>
           <subject>
               <name>SearchName</name>
           </subject>
       </search>
       <result>
           <history>
              <dob>HistoryDOB</dob>
           </history>
       </result>
    </personal>
  </report>
'

我在这里尝试的是 - 选择名称但这里的条件是

如果<personal>包含<result>，请选择name下的history/name
如果<personal>不包含<result>，请选择name下的subject/name
如果<personal>包含<result>但是名称不存在，则输入null

我正在使用以下查询

SELECT 
COALESCE(
   A.Search.value('(result/history/name)[1]','varchar(max)'),
   A.Search.value('(search/subject/name)[1]','varchar(max)')
) AS Name
FROM @xml.nodes('/report/personal') as A(Search)

它正在返回

 SearchName
 HistoryName
 SearchName

但它在第三种情况下失败了。

Answer 1

只需调整第二个HttpClient调用，专门请求您指定的内容 - 对于没有values的节点，您只需search/subject：

result

结果：

SELECT 
COALESCE(
   A.Search.value('(result/history/name)[1]','varchar(max)'),
   A.Search.value('(search[not(../result)]/subject/name)[1]','varchar(max)')
) AS Name
FROM @xml.nodes('/report/personal') as A(Search)

Answer 2

如果<personal>包含<result>，您可以使用exist方法进行搜索。

使用它，您的算法可以直接转换为查询：

select
    case 
        when A.Search.exist('result') = 1
            then A.Search.value('(result/history/name)[1]','varchar(max)')
        else A.Search.value('(search/subject/name)[1]','varchar(max)')
    end as Name
FROM @xml.nodes('/report/personal') as A(Search)

如何在Sql中读取xml时向COALESCE添加条件

2 个答案: