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Difference between revisions of "JDatabaseQuery"

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'''Simple Example'''
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 +
The following is a very simple use of the JDatabaseQuery class:
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<source lang="php">
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function getListQuery()
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{
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        $query = new JDatabaseQuery();
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        $query->select('*');
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        $query->from('#__categories');
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        return $query;
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}
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</source>
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 +
----
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'''Complex Example'''
 +
 +
Consider a case in which we have three tables called "property", "building" and "unit". The primary keys for these tables are "property_id", "building_id" and "unit_id", respectively. We want to build a method which returns the number of units associated with a property_id which is passed to our method. The unit table has no direct relationship to the property table. It does have a relationship to the building table, which in turn has a relationship to the property table. The following method will build the query and execute it, returning the value for which we're looking.
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<source lang="php">
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function countUnits($property_id)
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{
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        $db =& JFactory::getDBO();
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        $query = $db->getQuery(true);
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        $query->select('count(*)');
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        $query->from('#__pt_building AS b');
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        $query->leftJoin('#__pt_unit AS u ON b.building_id = u.building_id');
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        $query->where('b.property_id = '. (int) $property_id);
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        $db->setQuery($query);
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        return $db->loadResult();
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}
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</source>

Latest revision as of 19:36, 7 March 2011

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[Edit Descripton] Description:JDatabaseQuery

Contents

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' );

[Edit See Also] SeeAlso:JDatabaseQuery

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 = $db->getQuery(true);
        $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();
}