生成测试数据 T－SQL系列
在xyz表中创建100行
--Method 1. simple DEFAULT values on table
CREATE TABLE xyz
(
col1 int PRIMARY KEY IDENTITY(1,1) NOT NULL,
col2 int NOT NULL DEFAULT 999,
col3 char(10) NOT NULL DEFAULT ''ABCDEFGHIJK''
)
GO
DECLARE @counter int
SET @counter=1
WHILE(@counter<=100)
BEGIN
INSERT xyz DEFAULT valueS
SET @counter=@counter+1
END
SELECT * FROM
xyz
（2） RAND( ) 的一般用法
生成在一定范围的随机数
-- 0~9999
(CONVERT(int,RAND()*100000)%10000)
-- -9999~9999
CASE
WHEN (CONVERT(int,RAND()*100)%2=1 THEN
(CONVERT(int,RAND()*100000)%10000*-1)
ELSE (CONVERT(int,RAND()*100000)%10000)
END
-- A~Z
CHAR((CONVERT(int,RAND()*1000)%26)+65) --65 is A
（3） 若想确认每次执行RAND()函数是否产生不同的结果，应该为RAND()指定种子，即把一个整数置于圆括号中。可以用@@spid ，即新建表的object_id，或其它“几乎随机”的整数作为种子值。
IF (ISNULL(OBJECT_ID(''random_data''),0))>0
DROP TABLE random_data
GO
CREATE TABLE random_data
(
COL1 int PRIMARY KEY,
col2 int,
col3 char(15)
)
GO
DECLARE @counter int,@col2 int,@col3 char(15)
/*Insert 1000 rows of date */
--Seed Random generator
SELECT @counter=0,@col2=RAND(@@spid+cpu+physical_io)
FROM master..sysprocesses WHERE spid=@@spid
WHILE (@counter<1000)
BEGIN
SELECT @counter=@counter+10, --Sequence numbers by 10
@col2=
CASE --Random integer between -9999 and 9999
WHEN CONVERT(int,RAND()*100)%2=1
THEN (CONVERT(int,RAND()*100000)%10000*-1)
ELSE CONVERT(int,RAND()*100000)%10000
END,
@col3=
CHAR((CONVERT(int,RAND()*1000)%26)+65) --65 is A
+CHAR((CONVERT(int,RAND()*1000)%26)+65)
+CHAR((CONVERT(int,RAND()*1000)%26)+65)
+CHAR((CONVERT(int,RAND()*1000)%26)+65)
+REPLICATE(CHAR((CONVERT(int,RAND()*1000)%26)+65),11)
INSERT random_data valueS(@counter,@col2,@col3)
END
GO
SELECT * FROM random_data WHERE col1<200
用另一种方法实现：
CREATE TABLE random_data
(
COL1 int PRIMARY KEY IDENTITY(10,10) NOT NULL,
col2 int NOT NULL DEFAULT CASE
--Random integer between -9999 and 9999
WHEN CONVERT(int,RAND()*100)%2=1
THEN (CONVERT(int,RAND()*100000)%10000*-1)
ELSE CONVERT(int,RAND()*100000)%10000
END,
col3 char(15) NOT NULL DEFAULT
CHAR((CONVERT(int,RAND()*1000)%26)+65) --65 is A
+CHAR((CONVERT(int,RAND()*1000)%26)+65)
+CHAR((CONVERT(int,RAND()*1000)%26)+65)
+CHAR((CONVERT(int,RAND()*1000)%26)+65)
+REPLICATE(CHAR((CONVERT(int,RAND()*1000)%26)+65),11)
)
GO
DECLARE @counter int
SELECT @counter=1
WHILE (@counter<1000)
BEGIN
INSERT random_data DEFAULT valueS
SET @counter=@counter+1
END
GO
SELECT * FROM random_data WHERE col1<200
