SQL

Question

我需要从 SQL Server 数据库向下游传递一个值，这本质上是两个 timestamps 之间的区别。使用 DATEDIFF 函数就足够简单了。

SELECT DATEDIFF(day, '2015-11-06 00:00:00.000','2015-12-25 00:00:00.000') AS DiffDate ;

但是，在向下传递值时，代码只知道订单 ID 值，而不知道上面显示的 2 个时间戳。因此，我需要 timestamp 信息来自子查询，或者我认为的其他东西。子查询的主要细节在这里：

select O.DATE1 , C.DATE2
from TABLE1 O, TABLE2 C
WHERE O.VALUE1_ID = C.VALUE1
AND O.order_id = '12345678'

我尝试了几种不同的方法，但是 none 都成功了。最新的我已经厌倦了下面，从语法的角度来看它看起来不错，但我得到了错误：

Conversion failed when converting date and/or time from character string

我从来都不太确定如何应对或处理。

select DATEDIFF (day,'(select O.VALUE1 
from TABLE1 O 
where O.VALUE1 = 16650476)' , 
               '(SELECT C.VALUE1 
                 from TABLE1 O, TABLE2 C 
                 WHERE O.VALUE1 = C.VALUE2 AND O.order_id = 12345678)') AS DIFFDATE;

如有任何指点或帮助，我们将不胜感激。

Answer 1

我想你想要以下内容：

SELECT DATEDIFF(DAY, cj.SomeDateColumn, C.SomeDateColumn)
FROM TABLE1 O 
JOIN  TABLE2 C  ON O.VALUE1 = C.VALUE2
CROSS JOIN (SELECT O.SomeDateColumn FROM TABLE1 WHERE order_id = 16650476) cj
WHERE  O.order_id = 12345678

Answer 2

你能声明两个datetime变量然后datediff这两个变量吗？

DECLARE @FirstDate AS datetime
DECLARE @SecondDate AS datetime
SET @FirstDate = (select O.VALUE1 from TABLE1 O where O.VALUE1 = 16650476)
SET @SecondDate = (SELECT C.VALUE1 from TABLE1 O, TABLE2 C WHERE O.VALUE1 = C.VALUE2 AND O.order_id = 12345678)
SELECT DATEDIFF(day, @FirstDate, @SecondDate)

Answer 3

你能试试下面的方法吗？我已经使用了你的子查询，但有关表 "Table1" 和 "Table2" 中数据的更多信息会很有用

SELECT
    DATEDIFF(day, D.Date1, D.Date2) AS DiffDate 
FROM
(
    select O.DATE1 as Date1 , C.DATE2 as Date2
    from TABLE1 O, TABLE2 C
    WHERE O.VALUE1_ID = C.VALUE1
    AND O.order_id = '12345678' 
) D

您收到错误的原因

Conversion failed when converting date and/or time from character string

是因为您将字符串（下方）传递给 datediff 函数而不是使用日期

'(select O.VALUE1 
from TABLE1 O 
where O.VALUE1 = 16650476)'

Answer 4

子查询不应该是字符串，所以去掉单引号。另外，您谈论的是 O.DATE1 和 C.DATE2，所以您的意思可能是这样的：

select DATEDIFF (day, 
              (select O.DATE1 
                 from TABLE1 O 
                where O.VALUE1 = 16650476) , 
              (SELECT C.DATE2 
                from TABLE1 O, TABLE2 C 
                WHERE O.VALUE1 = C.VALUE2 AND O.order_id = 12345678)) AS DIFFDATE;

SQL - 带子查询的 DATEDIFF

SQL - DATEDIFF with a subquery

sql-server

datediff