XML tag parsing into a columns using XQuery

Question

I have below XML structure

<customMessages id="c928E0908E3A2482B91200B5ABDE4262B">
    <Referrals id="R05D2A8F94F5B44138E6CF43DA06AFB42">
        <message refObject="pB1F92D8F1F3442629052904FB4751602" flag="refer" 
                 category="(message)" controllingId="ReferralRules.IsBindableAssistant"     
                 messageName="ReferralRules.IsBindableAssistantMsg65"     
                 id="m79DD647217A54FC2AE7D129B095C29EC">Snow removal is performed for others &lt; 25,000</message>
        <message refObject="pB1F92D8F1F3442629052904FB4751602" flag="refer" 
                 category="(message)" controllingId="ReferralRules.IsBindableAssistant" 
                 messageName="ReferralRules.IsBindableAssistantMsg166" 
                 id="mABF6DE099DA04517A57D822B3DB0344D">Foreign Revenue</message>
        <message refObject="pB1F92D8F1F3442629052904FB4751602" flag="refer" 
                 category="(message)" controllingId="ReferralRules.IsBindableAssistant" 
                 messageName="ReferralRules.IsBindableAssistantMsg167" 
                 id="mEB086005E0124CF59EF3F8DBCC25C99A">US Revenue</message>
    </Referrals>
</customMessages>

I want an output as below

CustomMessageId  Message
id1               message1
id1               message2
id1               message3 .. n

Please note that message has multiple values

I am using below query

  Select 
      x.r.value('(@id)[1]', 'varchar(500)') as CustomMessageId,
      Case 
         When y.r.value('(message)[1]', 'varchar(500)') = '' 
            Then NULL 
         Else y.r.value('(message)[1]','varchar(500)') 
      End as message
  from
      (SELECT  
           Cast(XMLData as XML) XMLData
       FROM
           Table A) s
  CROSS apply 
      s.XMLData.nodes('session/customMessages') as x(r)
  CROSS apply 
      s.XMLData.nodes('session/customMessages/Referrals/message') as y(r)

However, I am getting only the first instance of message and not all the messages. Can anyone help?

Answer 1

Did you simplify your query some how or real data are different? that query "as is" must return:

CustomMessageId                                 Message
c928E0908E3A2482B91200B5ABDE4262B               NULL
c928E0908E3A2482B91200B5ABDE4262B               NULL
c928E0908E3A2482B91200B5ABDE4262B               NULL

I tested it and did not get "only first instance" I got NULL for all three.

Problem: XPath in nodes for y(r) and in yrvalue quite not correct.

you make a set of nodes from session/customMessages/Referrals/message and then try to get <message> node value again from <message> . It is not there and result is NULL.

to fix it you need to do either change line

s.XMLData.nodes('session/customMessages/Referrals/message') as y(r)

to

s.XMLData.nodes('session/customMessages/Referrals') as y(r)

or in all yrvalue functions use text() node as

y.r.value('(text())[1]', 'varchar(500)')

That is preferable from XPath point of view, but not critical.