Query to filter RelatedItemID column using CAML

Question

I have to filter RelatedItemID column from workflow task list using CAML query to get only those records that match the MAIN itemID from its corresponding main list. How do I achieve this? I tried the below query and it's surprising to know that it doesn't work, rather the query returns all records irrespective of the below filter that applied.

Answer 1

Per my test, I could reproduce you issue on my end.

Seems that the character ' cannot be encoded correctly, try to replace it with " and remove the slash \. Also you need to change the Eq to Contains.

Here is my demo for you:

   camlQuery.ViewXml =
      @"<View>  
            <Query> 
               <Where><Contains><FieldRef Name='RelatedItems' /><Value Type='RelatedItems'>[{&quot;ItemId&quot;:14,&quot;WebId&quot;:&quot;c1220a37-046e-4c95-9e32-803fd4d54caa&quot;,&quot;ListId&quot;:&quot;8bb17903-679e-4ef9-9826-d61b19289703&quot;}]</Value></Contains></Where> 
            </Query> 
             <ViewFields><FieldRef Name='RelatedItems' /></ViewFields> 
      </View>";