sql-server - 如何在 SQL Server 中生成具有正态分布的数字

Question

我正在尝试播种一些数据，是否有在 SQL Server 中生成遵循正态分布曲线的数字？

比如：我会指定平均值、标准差和计数，然后我会得到一个数字列表？

Answer 1

随机正态分布

UPDATE TABLE 
SET COLUMN = CAST(SQRT(-2*LOG(RAND()))*SIN(2*PI()*RAND(CHECKSUM(NEWID())))as decimal(5,3))    
from TABLE

Answer 2

引用http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=135026你可以试试

CREATE FUNCTION [dbo].[udf_NORMSDIST]
(
            @x FLOAT
)
RETURNS FLOAT
AS
/****************************************************************************************
NAME: udf_NORMSDIST
WRITTEN BY: rajdaksha
http://www.sqlteam.com/forums/topic.asp?TOPIC_ID=135026
DATE: 2009/10/29 
PURPOSE: Mimics Excel's Function NORMSDIST

Usage: SELECT dbo.udf_NORMSDIST(.5)


REVISION HISTORY

Date Developer Details
2010/08/11 LC Posted Function


*****************************************************************************************/

BEGIN 
DECLARE @result FLOAT
DECLARE @L FLOAT
DECLARE @K FLOAT
DECLARE @dCND FLOAT
DECLARE @pi FLOAT
DECLARE @a1 FLOAT
DECLARE @a2 FLOAT
DECLARE @a3 FLOAT
DECLARE @a4 FLOAT
DECLARE @a5 FLOAT

--SELECT @L = 0.0
SELECT @K = 0.0
SELECT @dCND = 0.0

SELECT @a1 = 0.31938153
SELECT @a2 = -0.356563782
SELECT @a3 = 1.781477937
SELECT @a4 = -1.821255978
SELECT @a5 = 1.330274429
SELECT @pi = 3.1415926535897932384626433832795

SELECT @L = Abs(@x)

IF @L >= 30
BEGIN
IF sign(@x) = 1
SELECT @result = 1
ELSE
SELECT @result = 0
END
ELSE
BEGIN
-- perform calculation
SELECT @K = 1.0 / (1.0 + 0.2316419 * @L)
SELECT @dCND = 1.0 - 1.0 / Sqrt(2 * @pi) * Exp(-@L * @L / 2.0) *
(@a1 * @K + @a2 * @K * @K + @a3 * POWER(@K, 3.0) + @a4 * POWER(@K, 4.0) + @a5 * POWER (@K, 5.0))
IF (@x < 0)
SELECT @result = 1.0 - @dCND
ELSE
SELECT @result = @dCND

END

RETURN @result
END

您显然可以抵消结果以更改平均值并将其包装在一个函数中以根据需要进行迭代以返回所需的样本点数量。如果您需要帮助，请告诉我。

Answer 3

例如（愚蠢的 SO 正文解析器）： http ://www.sqlservercentral.com/articles/SQL+Uniform+Random+Numbers/91103