问PostgreSQL LAG()函数可以引用它自己吗？

EN

SELECT i, EXP(SUM(LN(i)) OVER w)::int factorial
FROM generate_series(1, 10) i
WINDOW w AS (ORDER BY i ROWS BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW);
-- outputs:
 i  | factorial 
----+-----------
  1 |         1
  2 |         2
  3 |         6
  4 |        24
  5 |       120
  6 |       720
  7 |      5040
  8 |     40320
  9 |    362880
 10 |   3628800
(10 rows)

WITH RECURSIVE series AS (
  SELECT i FROM generate_series(1, 10) i
)
, rec AS (
  SELECT i, 1 factorial FROM series WHERE i = 1
  UNION ALL
  SELECT series.i, series.i * rec.factorial 
  FROM series 
  JOIN rec ON series.i = rec.i + 1
)
SELECT * 
FROM rec;

[1]: log(a * b * c) = log (a) + log (b) + log (c)
[2]: exp (log a) = a
[combining 1&2]: exp(log a + log b + log c) = a * b * c

when i equals 1 the values in this window frame are {1}
when i equals 2 the values in this window frame are {1,2}
when i equals 3 the values in this window frame are {1,2,3}