How to optimize collection sets

Question

I have a custom module that creates a sql table/collection with data added either by admin or users.

On certain pages this one collection is called a few times with specific filters to output specific data. See example below how i fetch/display the data.

$my_collection_set_A = Mage::getModel('collection/collection')->getCollection();
$my_collection_set_A->addFieldToFilter('created_time', array('gt' => date("Y-m-d H:i:s", strtotime('-1 day'))));
foreach($my_collection_set_A as $set_A_item){
echo $set_A_item->getId();
}

$my_collection_set_B = Mage::getModel('collection/collection')->getCollection();
$my_collection_set_B->addFieldToFilter('created_time', array('gt' => date("Y-m-d H:i:s", strtotime('-1 week'))));
foreach($my_collection_set_B as $set_B_item){
echo $set_B_item->getId();
}

$my_collection_set_C = Mage::getModel('collection/collection')->getCollection();
$my_collection_set_C->addFieldToFilter('created_time', array('gt' => date("Y-m-d H:i:s", strtotime('-1 month'))));
foreach($my_collection_set_C as $set_C_item){
echo $set_C_item->getId();
}

As you can see this is just simple collection filtering but is there a way just to call the collection once and filter later down the track (multiple times, different filters);

//Top of Page code (only call once)
$collection = Mage::getModel('collection/collection')->getCollection();
...
...
...
...
//called later down
$collection->addFieldToFilter('created_time', array('gt' => date("Y-m-d H:i:s", strtotime('-1 month'))));
foreach($collection as $item){
echo $item->getId();
}
...
...
...

//called again later down
$collection->addFieldToFilter('created_time', array('gt' => date("Y-m-d H:i:s", strtotime('-1 day'))));
foreach($collection as $item){
echo $item->getId();
}
...
...
etc

Surely this is possible as this would save alot of overheads (not calling the same collection multiple times, only once) especially as Ive got a lot of data to filter/output from the same collection on one page.

Answer 1

Try this

<?php
  //Top of Page code (only call once)
$collection1 = $collection2 = $collection3 = Mage::getModel('collection/collection')->getCollection();


//called later down
$collection1->getSelect()->reset('where');
$collection1->addFieldToFilter('created_time', array('gt' => date("Y-m-d H:i:s", strtotime('-1 month'))));
foreach($collection1 as $item){
echo $item->getId();
}


//called again later down
$collection2->getSelect()->reset('where');
$collection2->addFieldToFilter('created_time', array('gt' => date("Y-m-d H:i:s", strtotime('-1 day'))));
foreach($collection2 as $item){
echo $item->getId();
}

//called again later down
$collection3->getSelect()->reset('where');
$collection3->addFieldToFilter('created_time', array('gt' => date("Y-m-d H:i:s", strtotime('-1 week'))));
foreach($collection3 as $item){
echo $item->getId();
}