ElementsService::getTotalElements.php

<?php

/**
 * Returns the total number of elements that match a given criteria.
 *
 * @param ElementCriteriaModel $criteria An element criteria model that defines the parameters for the elements
 *                                       we should be counting.
 *
 * @return int The total number of elements that match the criteria.
 */
public function getTotalElements($criteria = null)
{
	// TODO: Lots in here MySQL specific.
	$query = $this->buildElementsQuery($criteria, $contentTable, $fieldColumns, true);

	if ($query)
	{
		$query
			->order('')
			->offset(0)
			->limit(-1)
			->from('elements elements');

		$elementsIdColumn = 'elements.id';
		$elementsIdColumnAlias = 'elementsId';
		$selectedColumns = $query->getSelect();

		// Normalize with no quotes. setSelect later will properly add them back in.
		$selectedColumns = str_replace('`', '', $selectedColumns);

		// Guarantee we select an elements.id column
		if (strpos($selectedColumns, $elementsIdColumn) === false)
		{
			$selectedColumns = $elementsIdColumn.', '.$selectedColumns;
		}

		// Replace all instances of elements.id with elementsId
		$selectedColumns = str_replace($elementsIdColumn, $elementsIdColumnAlias, $selectedColumns);

		// Find the position of the first occurance of elementsId
		$pos = strpos($selectedColumns, $elementsIdColumnAlias);

		// Make the first occurance of elementsId an alias for elements.id
		if ($pos !== false) {
			$selectedColumns = substr_replace($selectedColumns, $elementsIdColumn.' AS '.$elementsIdColumnAlias, $pos, strlen($elementsIdColumnAlias));
		}

		$query->setSelect($selectedColumns);

		$masterQuery = craft()->db->createCommand();
		$masterQuery->params = $query->params;

		$masterQuery->from(sprintf('(%s) derivedElementsTable', $query->getText()));

		$count = $masterQuery->count('derivedElementsTable.'.$elementsIdColumnAlias);

		return $count;
	}
	else
	{
		return 0;
	}
}