Query CRM 2011 with Outer Join

Question

I am using the code below to query the appointment set in CRM 2011. When I use this query it returns the data, but it returns duplicates. If I take out the Outer joins it doesn't return anything at all. Any ideas on how to fix this?

<fetch>
  <entity name="appointment">
    <attribute name="scheduledstart" />
    <link-entity name="systemuser" from="systemuserid" to="ownerid" link-type="outer">
      <attribute name="firstname" alias="ownerFirstName" />
      <attribute name="lastname" alias="ownerLastName" />
    </link-entity>
    <link-entity name="contact" from="contactid" to="new_contactperson" link-type="outer">
      <attribute name="parentcustomerid" alias="parentaccount" />
      <attribute name="new_businessunit" alias="businessunit" />
    </link-entity>
    <attribute name="new_contactperson" />
    <attribute name="subject" />
    <attribute name="new_coldernotes" />
    <link-entity name="activityparty" from="activityid" to="activityid" link-type="outer">
      <attribute name="participationtypemask" alias="participationtypemask" />
      <filter>
        <condition attribute="participationtypemask" operator="eq" value="5" />
      </filter>
      <link-entity name="contact" from="contactid" to="partyid" link-type="outer">
        <attribute name="fullname" alias="RequiredContactFullName" />
      </link-entity>
      <link-entity name="systemuser" from="systemuserid" to="partyid" link-type="outer">
        <attribute name="fullname" alias="RequiredOwners" />
      </link-entity>
      <link-entity name="account" from="accountid" to="partyid" link-type="outer">
        <attribute name="name" alias="RequiredAccount" />
      </link-entity>
    </link-entity>
    <!--the new join-->
    <link-entity name="activityparty" from="activityid" to="activityid" alias="optionalactivityparty" link-type="outer">
      <attribute name="participationtypemask" alias="optionalparticipationtypemask" />
      <filter>
        <condition attribute="participationtypemask" operator="eq" value="6" />
      </filter>
      <link-entity name="contact" from="contactid" to="partyid" alias="optionalcontact" link-type="outer">
        <attribute name="fullname" alias="OptionalContactFullName" />
      </link-entity>
      <link-entity name="systemuser" from="systemuserid" to="partyid" alias="systemuser2" link-type="outer">
        <attribute name="fullname" alias="OptionalOwners" />
      </link-entity>
      <link-entity name="account" from="accountid" to="partyid" alias="optionalaccount" link-type="outer">
        <attribute name="name" alias="OptionalAccount" />
      </link-entity>
    </link-entity>
    <filter type="and">
      <condition attribute="scheduledstart" operator="on-or-after" value="@FromDate" />
      <condition attribute="scheduledstart" operator="on-or-before" value="@ToDate" />
    </filter>
  </entity>
</fetch>

Thanks!

Answer 1

Try indicating that you want a distinct record set by changing your root fetch node to

<fetch distinct='true'>
...
</fetch>