DB queries

joomlaqueries.php

<?php
// Select record, all fields
$query = $db->getQuery(true)
	->select('*')
	->from($db->quoteName('#__table'))
	->where($db->quoteName('id') . ' = '. (int) $searchId);
$db->setQuery($query);
$results = $db->loadObjectlist();

// Select record, specific fields
$query = $db->getQuery(true)
	->select($db->quoteName(array('field1','field2','field3')))
	->from($db->quoteName('#__table'))
	->where($db->quoteName('id') . ' = ' . (int) $searchId);
$db->setQuery($query);
$results = $db->loadObjectList();

// Select record, one field
$query = $db->getQuery(true)
	->select($db->quoteName('field1'))
	->from($db->quoteName('#__table'))
	->where($db->quoteName('id') . ' = ' . (int) $searchId);
$db->setQuery($query);
$result = $db->loadResult();

// Select record, with join (id, titel from articles, username and name of author)
$query = $db->getQuery(true)
	->select($db->quoteName(array('a.id', 'a.title', 'u.username', 'u.name')))
	->from($db->quoteName('#__content', 'a'))
	->join('LEFT', $db->quoteName('#__users', 'u') . ' ON (' . $db->quoteName('a.created_by') . ' = ' . $db->quoteName('u.id') . ')');
$db->setQuery($query);
$results = $db->loadObjectlist();

// Update record
$query = $db->getQuery(true)
	->update($db->quoteName('#__table'))
	->set($db->quoteName('field1') . ' = \'' . $valueField1 . '\'')
	->where($db->quoteName('id') . ' = ' . (int) $searchId);
$db->setQuery($query)->execute();

// Insert record
$fieldValues = array($db->quote(NULL),$db->quote($valueField1),$db->quote($valueField2),$db->quote($valueField3));
$query = $db->getQuery(true)
	->insert($db->quoteName('#__table'))
	->values(implode(',', $fieldValues));
$db->setQuery($query)->execute();
$lastId = $db->insertid();
?>

// See aldso: https://docs.joomla.org/Selecting_data_using_JDatabase