CREATE TABLE functional_areas (functional_area_code VARCHAR2, functional_area_description VARCHAR2)
CREATE TABLE documents (access_count NUMBER, document_code VARCHAR2)
CREATE TABLE document_functional_areas (document_code VARCHAR2, functional_area_code VARCHAR2)

Find the average access counts of documents with functional area 'Acknowledgement'.
SELECT AVG(t1.access_count) FROM documents AS t1 JOIN document_functional_areas AS t2 ON t1.document_code = t2.document_code JOIN functional_areas AS t3 ON t2.functional_area_code = t3.functional_area_code WHERE t3.functional_area_description = "Acknowledgement"
SELECT AVG("t1"."access_count") FROM "documents" "t1" JOIN "document_functional_areas" "t2" ON "t1"."document_code" = "t2"."document_code" JOIN "functional_areas" "t3" ON "Acknowledgement" = "t3"."functional_area_description" AND "t2"."functional_area_code" = "t3"."functional_area_code"