Question

我有一个查询，我有一个名为tblBooking的表该表中有3列

Column Names BookingID StartTime  EndTime
Datatype         int     DateTime  DateTime

示例数据：

BookingID   StartTime    EndTime
    1         10:00       11:00
    2         11:00       12:00
    3         01:30       03:30

我需要比较两列StartTime EndTime

的值

查询是：我必须alloacte资源，例如。会议室这可以每天进行

between 10:00 am to 7:00 pm.

所以我需要根据时间检查会议室的可用性。考虑所有场景。这是我在接受采访时问到的一个问题，我无法回答，所以我需要找到如何做的方式

Answer 1

看看这个例子。您需要检查重叠时段，因此选择具有没有结果的日期时间将是正确的。

        |---|           PERIOD
--------------------------------------
|---|                  FINE
    |---|               FINE
    |------|            NOT FINE
        |---|           NOT FINE
         |-|            NOT FINE
           |------|     NOT FINE
            |---|       FINE
                |---|   FINE
    |-------------|     NOT FINE




DECLARE @tblBookings TABLE(
        BookingID INT,
        StartTime DATETIME,
        EndTime DATETIME
)

INSERT INTO @tblBookings SELECT 1, '01 Jan 2010 10:00:00', '01 Jan 2010 11:00:00'
INSERT INTO @tblBookings SELECT 2, '01 Jan 2010 11:00:00', '01 Jan 2010 12:00:00'

DECLARE @StartDate DATETIME,
        @EndDate DATETIME

--Inside        
SELECT  @StartDate = '01 Jan 2010 10:30:00',
        @EndDate = '01 Jan 2010 11:30:00'

SELECT  *
FROM    @tblBookings
WHERE   NOT( @EndDate <= StartTime OR @StartDate >= EndTime)

--Overlapping left      
SELECT  @StartDate = '01 Jan 2010 09:30:00',
        @EndDate = '01 Jan 2010 10:30:00'

SELECT  *
FROM    @tblBookings
WHERE   NOT( @EndDate <= StartTime OR @StartDate >= EndTime)

--Overlapping right     
SELECT  @StartDate = '01 Jan 2010 11:30:00',
        @EndDate = '01 Jan 2010 12:30:00'

SELECT  *
FROM    @tblBookings
WHERE   NOT( @EndDate <= StartTime OR @StartDate >= EndTime)

--Overlapping left and right
SELECT  @StartDate = '01 Jan 2010 09:30:00',
        @EndDate = '01 Jan 2010 12:30:00'

SELECT  *
FROM    @tblBookings
WHERE   NOT( @EndDate <= StartTime OR @StartDate >= EndTime)

--THIS ONE IS FINE
SELECT  @StartDate = '01 Jan 2010 09:00:00',
        @EndDate = '01 Jan 2010 10:00:00'

SELECT  *
FROM    @tblBookings
WHERE   NOT( @EndDate <= StartTime OR @StartDate >= EndTime)

Answer 2

你可以在where子句中有多个标准...
BETWEEN 可以比较多个日期和时间
例如：

where requestedStartTime not between startTime and endTime
and requestedEndTime not between startTime and endTime

Answer 3

您可以使用以下查询找到指定日期/时间范围与表格中所有现有日期/时间范围之间的所有“冲突”：

DECLARE @YourTable table (BookingID int,StartTime datetime,EndTime datetime)

INSERT INTO @YourTable VALUES (1, '2010-03-03 10:00am', '2010-03-03 10:30am')
INSERT INTO @YourTable VALUES (2, '2010-03-03 11:30am', '2010-03-03 01:30pm')

DECLARE @StartDate datetime
       ,@EndDate datetime

SELECT @StartDate='2010-03-03 9:00am'
      ,@EndDate='2010-03-03 10:15am'
;WITH AllDates AS
(
    SELECT @StartDate AS DateOf
    UNION ALL
    SELECT DATEADD(mi,30,DateOf) --smallest increment to consider is 30 minutes
        FROM AllDates
    WHERE DateOf<@EndDate
)
,Collisions AS
(SELECT
     * 
     FROM @YourTable         y
         INNER JOIN AllDates a ON a.DateOf>=y.StartTime AND a.DateOf<=y.EndTime
)
SELECT * FROM Collisions

输出：

BookingID StartTime               EndTime                 DateOf
--------- ----------------------- ----------------------- -----------------------
1         2010-03-03 10:00:00.000 2010-03-03 10:30:00.000 2010-03-03 10:00:00.000
1         2010-03-03 10:00:00.000 2010-03-03 10:30:00.000 2010-03-03 10:30:00.000

(2 row(s) affected)

SQL Server 2005.日期时间比较同一个表的两列

3 个答案: