CREATE TABLE projects (project_id NUMBER, project_details CLOB)
CREATE TABLE statements (statement_id NUMBER, statement_details CLOB)
CREATE TABLE accounts (account_id NUMBER, statement_id NUMBER, account_details CLOB)
CREATE TABLE ref_document_types (document_type_code CLOB, document_type_name CLOB, document_type_description CLOB)
CREATE TABLE documents (document_id NUMBER, document_type_code CLOB, project_id NUMBER, document_date TIME, document_name CLOB, document_description CLOB, other_details CLOB)
CREATE TABLE documents_with_expenses (document_id NUMBER, budget_type_code CLOB, document_details CLOB)
CREATE TABLE ref_budget_codes (budget_type_code CLOB, budget_type_description CLOB)

Return the budget type codes, budget type descriptions and document ids for documents with expenses.
SELECT T2.budget_type_code, T2.budget_type_description, T1.document_id FROM documents_with_expenses AS T1 JOIN ref_budget_codes AS T2 ON T1.budget_type_code = T2.budget_type_code
SELECT "T2"."budget_type_code", "T2"."budget_type_description", "T1"."document_id" FROM "documents_with_expenses" "T1" JOIN "ref_budget_codes" "T2" ON "T1"."budget_type_code" = "T2"."budget_type_code"