如何在给定范围之间插入1000个随机日期？

Question

我是sql server的新手.我需要生成从给定日期范围中选择的随机日期.就像员工的就业日期应该在2011-01-01和之间的任何地方2011-12-31.生成的日期应随机插入1000行表中.

任何人都可以用我的查询指导我吗？

Answer 1

declare @FromDate date = '2011-01-01'
declare @ToDate date = '2011-12-31'

select dateadd(day, 
               rand(checksum(newid()))*(1+datediff(day, @FromDate, @ToDate)), 
               @FromDate)

Answer 2

您可以简单地使用此查询。

DATEADD(DAY, ABS(CHECKSUM(NEWID()) % 364 ), '2011-01-01')

如果要从其他时间轴添加日期，则可以更改01-01-2011和364。364等于您要添加的天数。在这种情况下，它在01-01-2011和之间31-12-2011。
（31-12-2011也包括在内。）

例如，假设您要在2018-01-01和之间添加一个随机日期2018-01-31，则可以像这样更改查询。

DATEADD(DAY, ABS(CHECKSUM(NEWID()) % 31), '2018-01-01')

要插入（一行/日期），只需使用此...

DECLARE @rdate DATE = DATEADD(DAY, ABS(CHECKSUM(NEWID()) % 31), '2018-01-01')

INSERT INTO TableName ([DateColumn])
VALUES (@rdate);

输出量

+-----+------------+
| ID  | DateColumn |
+-----+------------+
| 01  | 2018-01-21 |
+-----+------------+

在线演示：SQLFiddle.com

要一次插入1000行...

DECLARE @rdate DATE
DECLARE @startLoopID INT = 1
DECLARE @endLoopID INT = 1000 -- Rows you want to add

WHILE @startLoopID <= @endLoopID
BEGIN
    SET @rdate = DATEADD(DAY, ABS(CHECKSUM(NEWID()) % 364 ), '2011-01-01');
    SET @startLoopID = @startLoopID + 1;

    INSERT INTO TableName ([DateColumn])
    VALUES (@rdate);
END

输出量

+--------+------------+
|  ID    | DateColumn |
+--------+------------+
| 10000  | 2010-04-07 |
| 10001  | 2010-07-29 |
| 10002  | 2010-11-18 |
| 10003  | 2010-05-27 |
| 10004  | 2010-01-31 |
| 10005  | 2010-08-26 |
|   ?    |     ?      |
| 20000  | 2010-06-26 |
+--------+------------+

在线演示：SQLFiddle.com

要更新现有行...

UPDATE TableName
SET [DateColumn] = DATEADD(DAY, ABS(CHECKSUM(NEWID()) % 364 ), '2011-01-01')
WHERE condition;

在线演示：SQLFiddle.com

Answer 3

我已经写了这个简单的函数,它返回日期范围之间的随机日期:

create function date_rand ( @fromDate date, @toDate date) returns date
as
begin

 declare @days_between int
 declare @days_rand int

 set @days_between = datediff(day,@fromDate,@toDate)
 set @days_rand  = cast(RAND()*10000 as int)  % @days_between

 return dateadd( day, @days_rand, @fromDate )
end

调用函数:

select dbo.date_rand( '1/1/2001', '10/1/2001' )

你可以将函数与行生成器结合起来:

;WITH Nbrs_3( n ) AS ( SELECT 1 UNION SELECT 0 ),
Nbrs_2( n ) AS ( SELECT 1 FROM Nbrs_3 n1 CROSS JOIN Nbrs_3 n2 ),
Nbrs_1( n ) AS ( SELECT 1 FROM Nbrs_2 n1 CROSS JOIN Nbrs_2 n2 ),
Nbrs_0( n ) AS ( SELECT 1 FROM Nbrs_1 n1 CROSS JOIN Nbrs_1 n2 ),
Nbrs ( n ) AS ( SELECT 1 FROM Nbrs_0 n1 CROSS JOIN Nbrs_0 n2 )
SELECT dbo.date_rand( '1/1/2001', '10/1/2001' )
FROM ( SELECT ROW_NUMBER() OVER (ORDER BY n)
FROM Nbrs ) D ( n )
WHERE n <= 1000 

EDITED

要生成随机数,请使用:

RAND(CHECKSUM(NEWID()))

而不是兰德()

编辑II

函数返回'在函数内'无效使用副作用运算符'rand'错误.这是因为我们不能使用像RAND()或NEWID()这样的非确定性函数.

解决方法是创建一个视图,如:

create view myRandomNumber as 
select cast( RAND(CHECKSUM(NEWID()))*1000 as int) as new_rand

然后在功能中使用它:

...
select @days_rand  = new_rand  % @days_between from myRandomNumber
...

或者简单的不要使用函数并在select上写expresion.我只写了一个函数,你一步一步解释解决方案.

declare @fromdate date
declare @todate date
set @fromdate = '1/1/2001'
set @todate = '10/1/2001'
;WITH Nbrs_3( n ) AS ( SELECT 1 UNION SELECT 0 ),
Nbrs_2( n ) AS ( SELECT 1 FROM Nbrs_3 n1 CROSS JOIN Nbrs_3 n2 ),
Nbrs_1( n ) AS ( SELECT 1 FROM Nbrs_2 n1 CROSS JOIN Nbrs_2 n2 ),
Nbrs_0( n ) AS ( SELECT 1 FROM Nbrs_1 n1 CROSS JOIN Nbrs_1 n2 ),
Nbrs ( n ) AS ( SELECT 1 FROM Nbrs_0 n1 CROSS JOIN Nbrs_0 n2 )
SELECT 
   dateadd( day, 
            cast( RAND(CHECKSUM(NEWID()))*1000 as int) % 
                         datediff(day,@fromDate,@toDate), 
            @fromDate )
FROM ( SELECT ROW_NUMBER() OVER (ORDER BY n)
FROM Nbrs ) D ( n )
WHERE n <= 1000 

你可以在这里测试这个查询.