Oracle to PostgreSQL

Question

有人能告诉我如何在PostgreSQL中转换以下Oracle SQL语句吗?我不明白…

SELECT 
MAX(TKI1.USER_ID)
KEEP(DENSE_RANK LAST ORDER BY TKI1.UPD_DATE NULLS FIRST)
OVER(PARTITION BY TKI1.NUMBER) AS  USER_ID         
FROM
USER_TABLE TKI1;

Answer 1

您可以使用:

SELECT MAX(CASE WHEN rnk = 1 THEN user_id END) OVER (PARTITION BY NUMBER)
AS user_id
FROM   (
SELECT user_id,
NUMBER,
RANK() OVER (PARTITION BY NUMBER ORDER BY UPD_DATE DESC NULLS LAST)
AS rnk
FROM   user_table
) t