如何从SQL Server中的“ ntext”列获取数据

Question

I am using sql server, In my table I have an "ntext" column.the data in ntext column is as below

"<?xml version="1.0" encoding="UTF-8"?>
<processEngine id="5000001" instanceName="bg-claritysql.excers">
   <controller heartBeat="2014-11-14T19:35:57"/>
   <loader heartBeat="2014-11-14T19:35:57" queueLength="1"/>
   <conditionWaitList queueLength="1"/>
   <retryWaitList queueLength="0"/>
   <actionWaitList queueLength="0"/>
   <PreConditionPipelineManager load="3.451246679588729E-7" noOfPipelines="2" queueLength="0"
                                recentLoad="8.510423949066926E-6">
           <pipeline heartBeat="2014-10-11T04:14:17" index="1" load="1.0022981644497761E-9"
                name="Pre Condition Pipeline 1"
                recentLoad="1.0022981684681825E-9"
                runTime="3"
                running="false"
                startTime="2014-10-11T04:14:17"/>
   </PreConditionPipelineManager>
   <PostConditionTransitionPipelineManager load="8.273414600907745E-7" noOfPipelines="3" queueLength="0"
  </processEngine>"

I want to get the heartBeat,name,recentLoad,runTime,running,startTime values. can any one help me how to do this using sql query.. Thanks in advance......

Answer 1

See below:

declare @str nvarchar(max) = '<processEngine id="5000001" instanceName="bg-claritysql.excers">
   <controller heartBeat="2014-11-14T19:35:57"/>
   <loader heartBeat="2014-11-14T19:35:57" queueLength="1"/>
   <conditionWaitList queueLength="1"/>
   <retryWaitList queueLength="0"/>
   <actionWaitList queueLength="0"/>
   <PreConditionPipelineManager load="3.451246679588729E-7" noOfPipelines="2" queueLength="0" recentLoad="8.510423949066926E-6">
           <pipeline heartBeat="2014-10-11T04:14:17" index="1" load="1.0022981644497761E-9"
                name="Pre Condition Pipeline 1"
                recentLoad="1.0022981684681825E-9"
                runTime="3"
                running="false"
                startTime="2014-10-11T04:14:17"/>
            <pipeline heartBeat="2014-10-11T04:14:17" index="1" load="1.0022981644497761E-9"
                name="Pre Condition Pipeline 1"
                recentLoad="1.0022981684681825E-9"
                runTime="3"
                running="false"
                startTime="2014-10-11T04:14:17"/>
   </PreConditionPipelineManager>
   <PostConditionTransitionPipelineManager load="8.273414600907745E-7" noOfPipelines="3" queueLength="0" />
  </processEngine>'

declare @xml xml = @str

select 
    t.value('(./controller/@heartBeat)[1]', 'datetime') as HeartBeat,
    t.value('(./PreConditionPipelineManager/@recentLoad)[1]', 'float') as RecentLoad,
    t.value('(./PreConditionPipelineManager/pipeline/@recentLoad)[2]', 'float') as PipelineRecentLoad,
    t.value('(./PreConditionPipelineManager/pipeline/@running)[1]', 'bit') as PipelineRunning,
    t.value('(./PreConditionPipelineManager/pipeline/@startTime)[1]', 'datetime') as PipelineStartTime
from 
    @xml.nodes('processEngine') as a(t)

You can use any XQuery expression. See http://msdn.microsoft.com/en-us/library/ms189075.aspx for more details.

Or you can update your table column to be of xml type instead of ntext and use a query like:

select 
    xmlcolumn.value('(./processEngine/controller/@heartBeat)[1]', 'datetime') as HeartBeat,
    xmlcolumn.value('(./processEngine/PreConditionPipelineManager/@recentLoad)[1]', 'float') as RecentLoad,
    xmlcolumn.value('(./processEngine/PreConditionPipelineManager/pipeline/@recentLoad)[2]', 'float') as PipelineRecentLoad,
    xmlcolumn.value('(./processEngine/PreConditionPipelineManager/pipeline/@running)[1]', 'bit') as PipelineRunning,
    xmlcolumn.value('(./processEngine/PreConditionPipelineManager/pipeline/@startTime)[1]', 'datetime') as PipelineStartTime
from 
    xmltable