sql server 2005下奇怪的Delete Top 语句

shirobert

　　sql server 2005中Delete语句可以添加一个top参数

以下示例删除 Testdb 表中所有行的 10%。  




--生成测试数据库
Create database Testdb
go
USE [Testdb]
GO
--生成测试表
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[TestDelete](
    [PKID] [int] IDENTITY(1,1) NOT NULL,
    [TestID] [int] NULL,
    [testString] [nvarchar](50) NULL,
CONSTRAINT [PK_TestDelere] PRIMARY KEY CLUSTERED
(
    [PKID] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]
go
--插入测试数据
declare @tmpID int
set @tmpID=1
WHILE ( (SELECT max(PKID) FROM TestDelete)