How to read child node in xml

Does anyone know how to read child nodes of xml in sql ?

I am trying it hard but not able to get it ??

below is my sample xml

<RequisitionRequest>
<Authentication>
<PartnerID>Provided By Client</PartnerID>
<SharedSecret>Provided By client</SharedSecret>
<PartnerVersion>client</PartnerVersion>
<IntegrationVersion>Provided By Agile1</IntegrationVersion>
<ClientDBKey>Provided By Agile1</ClientDBKey>
<RequestorID>J234</RequestorID>
</Authentication>
<JobPosting>
<ClientReferenceID>C112</ClientReferenceID>
<Requisition>
 <LanguageID>1</LanguageID>
</Requisition>
</JobPosting>

<Authentication>
<PartnerID>Provided By client</PartnerID>
<SharedSecret>Provided By client</SharedSecret>
<PartnerVersion>client</PartnerVersion>
<IntegrationVersion>Provided By client</IntegrationVersion>
<ClientDBKey>Provided By client</ClientDBKey>
<RequestorID>33234</RequestorID>
</Authentication>
<JobPosting>
<ClientReferenceID>C100</ClientReferenceID>
<Requisition>
  <LanguageID>2</LanguageID>
</Requisition>
</JobPosting>
<RequisitionRequest>

and want to pull the details of PartnerID, SharedSecret, PartnerVersion, IntegrationVersion, ClientDBKey, RequestorID, ClientReferenceID, LanguageID