我们如果要在sql server中，使用截取字符串的方法要怎样使用呢？
sql server提供了3个常用截取字符串方法，LEFT()、RIGHT()、SUBSTRING()
/****** Sql Server中截取字符串的常用方法 ******/ --1、LEFT()方法---
--函数说明---
--1）语法：LEFT(character,integer)
--2）介绍：参数1：要截取的字符串，参数2：截取字符个数
--3）使用：
--返回从字符串左边开始指定个数的字符--
select LEFT('SqlServer_2008',3)
--4）返回：Sql --1、RIGHT()方法---
-- right()函数说明---
--1）语法：RIGHT(character,integer)
--2）介绍：参数1：要截取的字符串，参数2：截取字符个数
--3）使用：
--返回从字符串右边开始指定个数的字符--
select LEFT('SqlServer_2008',4)
--4）返回：2008 --1、SUBSTRING()方法---
-- substring()函数说明---
--1）语法：SUBSTRING(character,start,length)
--2）介绍：参数1：要截取的字符串，参数2：开始截取的下标，参数3：截取的字符长度
--3）使用：
--返回从字符串中间的字符--
select SUBSTRING('SqlServer_2008',4,6)
--4）返回：Server
实例如下：
--截取字符串左边3个字符--
select LEFT('Welcome to China!',7) as 结果1
--截取字符串右边4个字符--
select RIGHT('Welcome to China!',6) as 结果2
--截取字符串中间6个字符（第二个从哪个字符下标开始）
select SUBSTRING('Welcome to China!',9,2) as 结果3
实例结果：
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参考来源地址：http://blog.csdn.net/hu_shengyang/article/details/10536881