How to use XQuery to retrieve data from XML

How to use XQuery to retrieve data from XML

XQuery is an Language that used to retrieve data from XML in required format, XQuery uses FLWOR expressions (For, Let, Where, Order By, Return), I am giving to some examples below to understand XQuery. By looking below example you should be able to retrieve data from XML using XQuery. 

Create One XML file and save as “Employee.xml”

xml version="1.0" encoding="utf-8" ?>

<Employees>

  <Employee type=”Admin”>

    <Name>Ritesh</Name>

    <DOB>Jun-23-2000</DOB>

    <DeptId>10</DeptId>

    <Salary>2000</Salary>

  </Employee>

  <Employee type=”Supervisor”>

    <Name>Kumar</Name>

    <DOB>Jan-20-2000</DOB>

    <DeptId>20</DeptId>

    <Salary>4000</Salary>

  </Employee>

</Employees>

Example-1: To Find the Department Id of the employee name 'Ritesh'

for $emp in doc (Employee.xml)/Employees/Employee

where $emp/Name =”Ritesh”

return $emp/DeptId 

Return Answer

<DeptId>10</DeptId>

If you want to return only data then use below return statement

return data($emp/DeptId) 

Return Answer

10

If you want to return Data in different Structure then use below return statement

return

  <Id>{data($emp/DeptId)}</Id>

Return Answer

  <Id>10</Id>

Example-2: To Find the Employee whose salary is > 1000 and return name with type

for $emp in doc("Employee.xml")/Employees/Employee

where $emp/Salary > 1000

order by $emp/Name

return
<Department>

if ($emp/@type=”Admin”)

then

<Admin>data($emp/Name)</Admin>

else

<Supervisor>data($emp/Name)</Supervisor>

</Department>

Return Answer
  <Department>

  <Admin>Kumar</Admin>

  <Supervisor>Ritesh</Supervisor>
  </Department>

You can find more examples http://www.w3schools.com/xquery/default.asp