查询错误:列名ICUSTAY_ID不明确。在BigQuery中使用多个子查询

SELECT subquery1.ICUSTAY_ID, subquery2.ICUSTAY_ID
FROM (
  SELECT ICUSTAY_ID
  FROM table1
) AS subquery1,
(
  SELECT ICUSTAY_ID
  FROM table2
) AS subquery2

WITH
subquery1 AS (
  SELECT ICUSTAY_ID AS ICUSTAY_ID_1
  FROM table1
),
subquery2 AS (
  SELECT ICUSTAY_ID AS ICUSTAY_ID_2
  FROM table2
)
SELECT subquery1.ICUSTAY_ID_1, subquery2.ICUSTAY_ID_2
FROM subquery1, subquery2

SELECT subquery1.ICUSTAY_ID_1, subquery2.ICUSTAY_ID_2
FROM (
  SELECT ICUSTAY_ID AS ICUSTAY_ID_1
  FROM table1
) AS subquery1,
(
  SELECT ICUSTAY_ID AS ICUSTAY_ID_2
  FROM table2
) AS subquery2