TO_DATE功能

Question

我尝试按照选择陈述：

SELECT  coalesce(rewards_Created_Activated_Failed.membership_id, expired.membership_id) AS MembershipID
   ,coalesce(date_sub(to_date(expired.occurred_at), 'YYY-MM-DD')
                    ,to_date((max_expiredDate.expiry_date), 'YYY-MM-DD')
                    ,to_date(rewards_Created_Activated_Failed.expiry_date), 'YYY-MM-DD') AS DateMembershipExpires

FROM (
    SELECT *,
                row_number() over (PARTITION BY membership_id ORDER BY status_change_date_time asc) AS RowNum
    FROM model.movie_membership_status
            WHERE event_name in ('MembershipCreatedEvent', 'MemberShipActivatedEvent')

 ) AS rewards_Created_Activated_Failed


LEFT JOIN
(
    SELECT membership_id
          ,max(status_change_date_time) as occurred_at
    FROM model.movie_membership_status
    WHERE event_name = 'MembershipExpiredEvent'
        GROUP BY membership_id
) expired

ON expired.membership_id = rewards_Created_Activated_Failed.membership_id

但是我收到以下错误：

  

错误：42883：函数to_date（没有时区的时间戳）不存在

如何修复该错误？

Answer 1

test=> \df to_date
                           List of functions
   Schema   |  Name   | Result data type | Argument data types |  Type  
------------+---------+------------------+---------------------+--------
 pg_catalog | to_date | date             | text, text          | normal
(1 row)

您必须提供所需的格式作为第二个参数。

请参阅the documentation。

Answer 2

看起来expired.occurred_at，max_expiredDate.expiry_date和rewards_Created_Activated_Failed.expiry_date已经是日期。这意味着您无需在其上调用to_date。此外，redshift中没有date_sub函数。我不确定你在那里做什么，但也许看看DATEDIFF？

你可能想要这样的东西（命令匹配你以前的合并声明）：

coalesce(
  rewards_Created_Activated_Failed.expiry_date,
  expired.occurred_at,
  max_expiredDate.expiry_date
) AS DateMembershipExpires