Distinguish between keyspaces at FROM level and subquery

I see difference in the result of a subquery on n1ql vs sql with same alias in outer and inner subquery for the same bucket/table name.

SELECT * FROM  default  t_1   WHERE   int_field1  NOT IN (SELECT * FROM  default  t_1   WHERE    

((t_1.bool_field1 AND t_1.decimal_field1 <= 4953)));

This query uses the same alias in outer and inner subquery , hence it gives this result for n1ql:

    "msg": "Duplicate subquery alias t_1",

But for sql the same query works. SQL checks for duplicate alias inside the same subquery but n1ql enforces it in outer and inner subquery.