Snowflake SQL 错误 - 函数“-”的参数类型无效：(TIMESTAMP_NTZ(9), TIMESTAMP_NTZ(9))

Posted 2023-05-09

【中文标题】Snowflake SQL 错误 - 函数“-”的参数类型无效：(TIMESTAMP_NTZ(9), TIMESTAMP_NTZ(9))

【英文标题】：Snowflake SQL error - Invalid argument types for function '-': (TIMESTAMP_NTZ(9), TIMESTAMP_NTZ(9))

【发布时间】：2019-10-07 19:42:22

【问题描述】：

当我尝试减去时间戳并执行窗口函数（lead、lag 和 partition by）时出现此错误：

函数“-”的参数类型无效：(TIMESTAMP_NTZ(9), TIMESTAMP_NTZ(9))

试过date_diff，但不能和窗口函数一起工作

SELECT 
   user_id,
   event,
   received_at,
   received_at - LAG( received_at,1) OVER (PARTITION BY user_id ORDER BY received_at) AS last_event
FROM 
   segment_javascript.help_center_opened

【参考方案1】：

您不能通过仅减去两个日期来获得数字来执行“Oracle 方式”，您必须使用具有度量单位/比例的 diff 函数，例如：

SELECT 
   ts, 
   TIMESTAMPDIFF(MILLISECONDS, LAG(ts, 1) OVER (ORDER BY ts), ts) tsd
FROM 
   (VALUES (CURRENT_TIMESTAMP), (DATEADD(DAY, 1, CURRENT_TIMESTAMP))) v(ts);

【讨论】：

我倾向于使用 DATEDIFF，因为它们的功能相同，但 DATEDIFF 更短docs.snowflake.net/manuals/sql-reference/functions/…

【参考方案2】：

我想您需要计算相同 user_id 与上次事件接收时间的时差。

如果是这样，我认为这会起作用：

SELECT 
   user_id,
   event,
   received_at,
   DATEDIFF(
     MINUTE, -- or any other supported date/time part
     received_at, -- start time 
     LAG( received_at,1) OVER (PARTITION BY user_id ORDER BY received_at) -- end time
     ) AS last_event
FROM 
   segment_javascript.help_center_opened