sql查询like和charindex和substring比较性能测试

300万条记录 like 和 charindex 函数以及substring函数性能比较：环境：sql2005数据量：300万查询结果数据量:2849999机器环境P4 3.0双核 2G内存1. 执行语句表结构：

USE [Test]
GO
/****** 对象:  Table [dbo].[TabTest]    脚本日期: 03/22/2011 09:46:20 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO
CREATE TABLE [dbo].[TabTest](
[id] [int] IDENTITY(1,1) NOT NULL,
[ypmc] [nvarchar](50) NULL,
[ypdm] [nvarchar](50) NULL,
[cdmc] [nvarchar](50) NULL,
[cddm] [nvarchar](50) NULL,
[gg] [nvarchar](50) NULL,
[list] [nvarchar](50) NULL,
[doc1] [nvarchar](50) NULL,
[ywuserid] [int] NULL,
[flag] [tinyint] NULL,
[flagstr] [nchar](10) NULL
) ON [PRIMARY]

/*仅list字段建聚集索引*/
select * from TabTest where list like '%a%' and ywuserid=10215
select * from TabTest where charindex('a',list)>0 and ywuserid=10215
select * from TabTest where substring(list ,1,1) = 'a' and ywuserid=10215
/*仅list字段建非聚集索引*/
select * from TabTest where list like '%a%' and ywuserid=10215
select * from TabTest where charindex('a',list)>0 and ywuserid=10215
select * from TabTest where substring(list ,1,1) = 'a' and ywuserid=10215
/*list字段不建索引*/
select * from TabTest where list like '%a%' and ywuserid=10215
select * from TabTest where charindex('a',list)>0 and ywuserid=10215
select * from TabTest where substring(list ,1,1) = 'a' and ywuserid=10215
/*查询字段和list建索引*/
select * from TabTest where list like '%a%' and ywuserid=10215
select * from TabTest where charindex('a',list)>0 and ywuserid=10215
select * from TabTest where substring(list ,1,1) = 'a' and ywuserid=10215
/*全部字段和list建索引*/
select * from TabTest where list like '%a%' and ywuserid=10215
select * from TabTest where charindex('a',list)>0 and ywuserid=10215
select * from TabTest where substring(list ,1,1) = 'a' and ywuserid=10215

仅list字段建聚集索引性能分析：

仅list字段建非聚集索引性能分析：

字段不建索引性能分析：

看到上面结果后：试了一下如下查询：

/*查询300万条*//*仅list字段建聚集索引*/select * from TabTest where list like '%a%'select * from TabTest where charindex('a',list)>0select * from TabTest where substring(list ,1,1) = 'a'/*仅list字段建非聚集索引*/select * from TabTest where list like '%a%'select * from TabTest where charindex('a',list)>0select * from TabTest where substring(list ,1,1) = 'a'/*list字段不建索引*/select * from TabTest where list like '%a%'select * from TabTest where charindex('a',list)>0select * from TabTest where substring(list ,1,1) = 'a'

/*list字段不建索引*/

/*仅list字段建非聚集索引*/

/*仅list字段建聚集索引*/

自己看看性能比较结果吧！