Question

如何从下表中查找总天数？我尝试使用DATEDIFF函数，但我无法得到我的结果。

date                      days 
-------------------------------
2017/11/10
2017/11/12
2017/11/15

天之间的差异应该是

2017/11/12-2017/11/10, 2017/11/15-2017/11/12.

Answer 1

您可以使用LAG（SQL Server 2012及更高版本）：

CREATE TABLE t(d DATE);
INSERT INTO t(d)VALUES ('2017-11-10'), ('2017-11-12'), ('2017-11-15');

SELECT *, DATEDIFF(day, LAG(d) OVER(ORDER BY d ASC),d)
FROM t;

<强> Rextester Demo

对于SQL Server 2005，您可以使用：

SELECT s.*, DATEDIFF(day, s2.d, s.d) AS days
FROM (SELECT *,  ROW_NUMBER() OVER(ORDER BY d) AS rn FROM t) s
LEFT JOIN (SELECT *,  ROW_NUMBER() OVER(ORDER BY d) AS rn FROM t) s2
  ON s.rn = s2.rn+1;

<强> Rextester Demo2

SQL Server日期差异

1 个答案: