In essence, you want to use your document list as a lookup table to extract the appName based on appId, right?
You’ll loop over the items in your string list and use an QueryXMLNode statement in the loop to locate the appName item where apps\appId=’%stringlist_appID%’
However, since you can’t use the % substitution variable inside an XQL query, you have to add another step.
Create a document with the same structure as the fields documentList but with only a single entry and some temporary name.
Use a map step to format the XQL query portion of the fields documentList with the substitution variable containing your appId element from the string list.
Then use a map statement with the appendToDocumentList transformer to
add your temporary document into a documentList with the same structure as the fields input parameter
Now instead of manually populating the fields parameter in Developer, just map the documentLIst you created. You won’t see the resulting variable, in Developer, but it will be available for mapping and you will see the results when you step though the Flow.
Clear as mud?