API16:JDatabaseQuery

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Defined in

libraries/joomla/database/databasequery.php

Methods

Method name	Description
clear	Clear data from the query or a specific clause of the query.
select
delete
insert
update
from
join
innerJoin
outerJoin
leftJoin
rightJoin
set
where
group
having
order
__toString	string The completed query

Importing

jimport( 'joomla.database.databasequery' );

Examples

<CodeExamplesForm />

Simple Example

The following is a very simple use of the JDatabaseQuery class:

function getListQuery()
{
        $query = new JDatabaseQuery();
        $query->select('*');
        $query->from('#__categories');
        return $query;
}

---

Complex Example

Consider a case in which we have three tables called "property", "building" and "unit". The primary keys for these tables are "property_id", "building_id" and "unit_id", respectively. We want to build a method which returns the number of units associated with a property_id which is passed to our method. The unit table has no direct relationship to the property table. It does have a relationship to the building table, which in turn has a relationship to the property table. The following method will build the query and execute it, returning the value for which we're looking.

function countUnits($property_id)
{
        $db =& JFactory::getDBO();
        $query = new JDatabaseQuery();
        $query->select('count(*)');
        $query->from('#__pt_building AS b');
        $query->leftJoin('#__pt_unit AS u ON b.building_id = u.building_id');
        $query->where('b.property_id = '. (int) $property_id);
        $db->setQuery($query);
        return $db->loadResult();
}