PHP：从MySQL选择多个count（id）作为一个查询

Question

I need to optimize the following code in one query :

        $query = 'select count(id) as featured_ads from #___properties  WHERE featured = 1 and approved =1';
    $db->setQuery($query);
    $featured_ads = intval($db->loadResult());


    $query = 'select count(id) as wait_ads from #___properties  WHERE approved =0 and canceled<>"1" ';
    $db->setQuery($query);
    $wait_ads = intval($db->loadResult());


    $query = 'select count(id) as total_users from #__sresuad WHERE gid = 18 ';
    $db->setQuery($query);
    $total_users = intval($db->loadResult());

What should I do?

Answer 1

You want all the counts to be returned in one query? A simple way to address this is to just have all your SELECTs define fields for an outer SELECT:

SELECT
    (select count(id) from #___properties  WHERE featured = 1 and approved =1) AS featured_ads,
    (select count(id) from #___properties  WHERE approved =0 and canceled<>"1") AS wait_ads,
    (select count(id) from #__sresuad WHERE gid = 18) AS total_users

As suggested by Lodder in his comment, writing SQL queries by hand is prone to errors and security lapses, so you might want to avoid it if possible.