How to get data from database using wcf service?

In my table duplicated ID value is their,that's reason,

Example data:Employee

ID Name Job DeptName Loc

1 a Mgr sales USA

1 a xxx ffff UK


I want to display data like below

<Employees>

<ID>1</ID>

<NAME>a</NAME>

<DEPTS>

<Dept>

<Job>mgr</Job>

<DeptName>sales</DeptName>

<Dept>

<Dept>

<Job>xxx</Job>

<DeptName>fff</DeptName>

<Dept>

</DEPTS>

<EMPLOYEES>

I want this type of output,database values

Can you give me the code for this,How can i start?