public static Expression from(QualifiedName name) {
    Expression result = null;

    for (String part : name.getParts()) {
      if (result == null) {
        result = new Identifier(part);
      } else {
        result = new DereferenceExpression(result, new Identifier(part));
      }
    }

    return result;
  }
If this DereferenceExpression looks like a QualifiedName, return QualifiedName. Otherwise
return null
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/relational/sql/ast/DereferenceExpression.java