如何获取两个日期戳之间的时间差并按降序排列答案

【问题标题】：How to get the time difference between two date stamps and arrange in DESCENDING ORDER如何获取两个日期戳之间的时间差并按降序排列
【发布时间】：2019-10-24 12:54:11
【问题描述】：

我需要以小时为单位的两个日期戳之间的时间差，并且需要按降序排列它们以获得中位数

SELECT "fulfillmentshistories"."fulfillmentid" as "Fulfillment ID" FROM FULFILLMENTHISTORIES
WHERE (Fulfillments."status" IN ('paid','delivered') AND (DATE("fulfillmenthistories"."createdAt") BETWEEN DATE('{{startDate}}') AND DATE('{{endDate}}')))
union
SELECT DATEDIFF(HOUR,   'startDate'-'endDate') as DATEDIFF;
ORDER BY DATEDIFF, DESC

这是我试过的，请帮忙

SELECT "fulfillmentshistories"."fulfillmentid" as "Fulfillment ID" FROM    FULFILLMENTHISTORIES
WHERE (Fulfillments."status" IN ('paid','delivered') AND (DATE ("fulfillmenthistories"."createdAt") BETWEEN DATE('{{startDate}}') AND DATE('{{endDate}}')))
union
SELECT DATEDIFF(HOUR,   'startDate'-'endDate') as DATEDIFF;
ORDER BY DATEDIFF, DESC

运行查询时出错：“ORDER”第 5 行或附近的语法错误：ORDER BY DATEDIFF, DESC ^

【问题讨论】：

as DATEDIFF; ORDER BY DATEDIFF, DESC 应该是as DATEDIFF ORDER BY DATEDIFF DESC

标签： sql redash

【解决方案1】：

SELECT DATEDIFF(HOUR, 'startDate'-'endDate') as DATEDIFF; ORDER BY DATEDIFF, DESC

应该是

SELECT DATEDIFF(HOUR, 'startDate'-'endDate') as DATEDIFF ORDER BY DATEDIFF, DESC ;

并尽量避免使用与函数名相似的别名。

【讨论】：

我还没有看到任何变化
运行查询时出错：在“DESC”第 4 行或附近出现语法错误：...'startDate'-'endDate') as DATEDIFF ORDER BY DATEDIFF, DESC ; ^ 这是我遇到的错误。
第二个 SELECT 语句是否也需要 FROM 子句？

【解决方案2】：

UNION
SELECT DATEDIFF(HOUR,   'startDate'-'endDate') as DATEDIFF;
ORDER BY DATEDIFF, DESC

应该是

UNION
SELECT DATEDIFF(HOUR,   'startDate'-'endDate') as DATEDIFF
ORDER BY DATEDIFF DESC;

删除 DATEDIFF 后的分号和 ORDER BY DATEDIFF 后的逗号。分号应该放在 SQL 语句的末尾，因为整个语句就是一个 sql 语句。

【讨论】：