function subraya(){
return GroupedList::create(carspecification::get()->leftJoin("carspecificationscategory", "\"carspecificationscategory\".\"ID\" = \"carspecification\".\"CarSpecificationsCategoryID\"")->filter(array('CarsID' => $this->CarsID,'CarSpecificationsTypeID' => '4')));
}

<% loop $subraya.GroupedBy(CarSpecificationsCategoryID) %>
<h3>$getCarSpeficCatName.Title</h3>
<ul>
<% loop $Children %>
<li>$Title </li>
<% end_loop %>
</ul>
<% end_loop %>

What is the issue with this code everthing works properly but '$getCarSpeficCatName.Title' is not displaying anything

Please help me..

Is getCarSpeficCatName defined on your car specification model?

See the examples at http://doc.silverstripe.org/framework/en/howto/grouping-dataobjectsets

public function getCarSpeficCatName () {
return $this->Title;
}

add in car carspecificationscategory model class

What i want is Group based on Category ,

CarSpecificationsPage.php

function subraya(){
return GroupedList::create(carspecification::get()->leftJoin("carspecificationscategory", "\"carspecificationscategory\".\"ID\" = \"carspecification\".\"CarSpecificationsCategoryID\"")->filter(array('CarsID' => $this->CarsID,'CarSpecificationsTypeID' => '4')));
}
I am querying join 2 table one 'carspecification' other one is 'carspecificationscategory' table

carspecification table is have this feilds
ID
ClassName
Created
LastEdited
Title
CarSpecificationsCategoryID
CarSpecificationsTypeID
Title Value
CarsID
TitleValue

carspecificationscategory
ID
ClassName
Created
LastEdited
Title

i need something like in view

CategoryTitle1 - this from carspecificationscategory
Title1 - this from carspecification
title2 - this from carspecification
CategoryTitle2 - this from carspecificationscategory
Title1 - this from carspecification
title2 - this from carspecification

<% loop $subraya.GroupedBy(CarSpecificationsCategoryID) %>
<h3>$carspecificationscategory.Title</h3>
<ul>
<% loop $Children %>
<li>$Title </li>
<% end_loop %>
</ul>
<% end_loop %>

is ther any easy way to achieve this please explain

I have a similar issue to sort out. Hope this is useful

-My first approach was create ArrayList including grouped information
$youritems = new ArrayList();
$youritems->push(new ArrayData( array('title' => myTitle, 'category' => groupA)))

-Then create GroupedList based on your ArrayList
GroupedList::create($youritems->sort('category'));

Then display on your template

<% loop youritems %>
<% loop $Children %>
$title
<% end_loop %>
<% end_loop %>