code: public List<StmtEphemeralTableScan> getEphemeralTableScans() {
          List<StmtEphemeralTableScan> scans = new ArrayList<>();
          if (m_joinTree != null) {
              m_joinTree.extractEphemeralTableQueries(scans);
          }
          return scans;
      }
docs: Get a list of the table subqueries used by this statement.  This method
  may be overridden by subclasses, e.g., insert statements have a subquery
  but does not use m_joinTree.