Question

我需要在一个查询中优化以下代码：

        $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());

我该怎么办？

Answer 1

您希望在一个查询中返回所有计数吗？解决这个问题的一个简单方法就是让所有SELECTs为外部SELECT定义字段：

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

正如Lodder在他的评论中所建议的那样，手工编写SQL查询容易出错和安全漏洞，所以如果可能的话你可能想避免它。

PHP：从MySQL中选择多个count（id）作为一个查询

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