小编Heb*_*dly的帖子

XPath 1.0中是否有一个运算符在SQL中充当"in"运算符？

select * from tbl_students where id in (1,2,3)

如何从以下使用C#的ContractID为2的xml文件中选择最后1个状态？

<actions>
     <Action>
    <ID>2</ID>
    <ContractID>1</ContractID>
    <EmployeeID>1</EmployeeID>
    <Date>2012-09-04 00:00:00.000</Date>
    <Reply/>
    <Status>4002</Status>
</Action>
    <Action>
    <ID>2</ID>
    <ContractID>2</ContractID>
    <EmployeeID>1</EmployeeID>
    <Date>2012-09-04 00:00:00.000</Date>
    <Reply/>
    <Status>4005</Status>
</Action>
    <Action>
    <ID>2</ID>
    <ContractID>2</ContractID>
    <EmployeeID>1</EmployeeID>
    <Date>2012-09-04 00:00:00.000</Date>
    <Reply/>
    <Status>4008</Status>
</Action>
</actions>

以及如何使用linq to xml或任何其他方式选择top n

什么是xml代码的linq,相当于以下的sql查询:

Select contracts.ID, contracts.ContractNo, 
    (select FieldName from tbl_SysType where ID =
    (select top 1 status from tbl_EmployeesActions where ContractID=contracts.ID and Status is not null order by ID desc ))as ContractStatus
from tbl_Contracts as contracts

如果有包含Contracts.xml,SysType.xml和EmployeesActions.xml的xml文件,则如下所示:Contracts.xml

<Contracts>
     <Contract>
    <ID>1</ID>
    <ContractNo>Mob124444</ContractNo>      
</Contract>
    <Contract>
    <ID>2</ID>
    <ContractNo>Mob124445</ContractNo>      
</Contract>
</Contracts>

EmployeesActions.xml …