LINQ to SQL使用=>不允许对String操作 [英] LINQ to SQL use of => operand on String not allowed

问题描述

可能重复:
​​ string1> =在Linq to SQL中未实现的string2，有工作空间吗?

Possible Duplicate:
string1 >= string2 not implemented in Linq to SQL, any workarround?

要简要说明我要实现的目标，我们有一个名为Application的表，它存储应用程序的版本号.例如，该表的内容是

To give a brief summary of what I want to achieve we have a table called Application and it stores application version numbers. The contents of that Table for example is

ApplicationID          VersionID
1                      R1.01.01.01
2                      C8.00.00.01
2                      C8.00.00.02
2                      R8.10.00.00
2                      R8.20.00.02
2                      R9.00.00.01
2                      R9.00.00.02
2                      R9.00.00.03
3                      R7.00.30.00

当我在TSQL中执行此查询时，没有任何问题，并且得到了正确的结果(请注意，VersionID是nvarchar类型)

When I am doing this query in TSQL, there are no problems and I get the correct results (Take note that the VersionID is nvarchar type)

Select * From Applications where VersionID >= 'R9.00.00.01' and ApplicationID = 2

但是当我像这样开始使用LINQ to SQL

but when I start using LINQ to SQL like such

var Applications = from v in db.Applications 
                   where v.VersionID.StartsWith("R") 
                   && v.VersionID >= "R9.00.00.01" 
                   && v.ApplicationID == 2
                   orderby v.VersionID
                   select v;

然后我得到一个错误:运算符> =不能应用于类型为'string'和'string'的操作数

Then I get the error "Operator >= cannot be applied to operands of type 'string' and 'string'

我如何在LINQ to SQL中实现这一点而不更改数据库端的任何内容?

How do I achive that in LINQ to SQL without changing anything on the database side?

推荐答案

使用 string.Compare() ?

&& string.Compare( v.VersionID , "R9.00.00.01"  ) >= 0

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