Sql 如何将datetime转换为datetime2?
我对一个查询有一个问题,当前where子句中使用了不同表中的两个字段来过滤数据。由于一个是datetime,另一个是datetime2,我得到了Sql 如何将datetime转换为datetime2?,sql,sql-server,datetime,Sql,Sql Server,Datetime,我对一个查询有一个问题,当前where子句中使用了不同表中的两个字段来过滤数据。由于一个是datetime,另一个是datetime2,我得到了 "Conversion failed when converting date and/or time from character string" error. 以下是查询: /*| 1) SELECT - ABSENCES AND SCHEDULES |*/ ------------------------------------------
"Conversion failed when converting date and/or time from character string" error.
以下是查询:
/*| 1) SELECT - ABSENCES AND SCHEDULES |*/
------------------------------------------
-- Retrieve data of absences
DECLARE @SADate AS DATETIME2(7)
SET @SADate = '2012-12-02'
-- Retrieve absences that have a supply teacher and are within the current date.
SELECT SAStaffID
,LastName + ', ' + FirstName AS FullName
,SADate
,SSPeriod
,SSCourseCode
,SSRoom
FROM tblOCStaffAbsent -- Join the staff schedule of the absent teacher that has a supply.
INNER JOIN tblOCStaffSchedule S
ON tblOCStaffAbsent.SAStaffID = S.SSStaffID
AND @SADate BETWEEN S.SSStartDt AND S.SSEndDt
INNER JOIN tblStaff SF
ON SF.StaffID = SAStaffID
INNER JOIN tblUsers U
ON U.UserID = SF.StaffUserID
WHERE SASupplyID IS NOT NULL
AND SADate = @SADate
--------------------------------
/*| 2) SELECT - SUPERVISIONS |*/
--------------------------------
--Union the supervisions
UNION ALL
SELECT SSupStaffID
,SupervisionDt
,CASE WHEN SSupPeriodHalf IS NOT NULL THEN SSupPeriod + '-' + SSupPeriodHalf
ELSE SSupPeriod
END AS FullPeriod
,'(SP) ' + SSupLocation
,NULL AS SSupRoom
,SSupMIDent
FROM tblOCStaffSupervisions
WHERE SupervisionDt = @SADate
SADate是tblOCStaffAbsent中的datetime字段,SupervisionDt是tblOCStaffSupervisions中的datetime2字段。来自tblOCStaffSupervisions表的SupervisionDt值可能是datetime数据类型。@SADate='2012-12-02'是一个字符串@SADate应该在DateTime数据类型中设置。如果仔细查看错误消息,将
DateTime
与DATETIME2
进行比较并不是问题,sql server可以毫无问题地完成这项操作
您将某些内容存储为字符串,但正在尝试将其转换为DATETIME2
转换为DATETIME2
的操作与其他转换一样convert(DATETIME2,MyDatetimeField)
只需知道DATETIME2
比DATETIME
具有更高的精度。您的数据不会更改,只有以更高精度添加的新信息才会使用它
看看下面的例子。两行将产生相同的结果
DECLARE @Datetime DATETIME = '03/21/2014 15:23:34.444'
SELECT @Datetime
UNION ALL
SELECT CONVERT(DATETIME2, @Datetime)
但在以下情况下
DECLARE @datetime2 DATETIME2 = SYSDATETIME();
SELECT @datetime2
UNION ALL
SELECT CONVERT(DATETIME, @datetime2)
第一次选择将产生比第二次选择更高的精度点将日期转换为字符串以进行比较?不能将@SADAte用作Datetime吗?SSStartDt和SSEndDt是什么数据类型?因为您只关心日期部分。我只想使用
DATE
SSStartDt和SSEndDt都是datetime是的。这篇帖子有点滑稽,因为他说“因为一个是datetime,另一个是datetime2”,错误明确地说:这涉及到一个字符串,伙计;)