yii - 如何在yii2查询构建器中基于子查询在where条件中编写if条件

Question

我在主查询中有一个子查询，如下所示:

$subquery = (new Query())->select('COUNT(project_sup_id)')
    ->from('project_supervisors AS sup')
    ->where(['AND','sup.project_ref_id = p.project_id']);

$uQuery =(new Query())->select(['project_id','supcount' => $subquery])
    ->from('projects AS p')
    ->join('LEFT JOIN','project_supervisors AS sup','sup.project_ref_id = project_id')
    ->andWhere('IF(supcount>0, sup_project_status=1, project_status=1)');

我正在尝试根据逻辑编写 where 条件，即，如果从子查询获得的计数大于零，则 where 条件必须为 sup_project_status=1否则 project_status=1 .在普通的Mysql中，很容易在where里面写if条件，但在yii2中我不明白如何写。

Answer 1

尝试将 yii\db\Expression 用于 RDBMS 原生表达式:

->andWhere(new yii\db\Expression('IF(supcount>0, sup_project_status=1, project_status=1)'));

您可以使用以下方法检查您的 SQL:

echo $uQuery->createCommand()->getRawSql();

它通过 Query 对象返回准备好的 SQL 命令。你也可以将整个 SQL 写成 yii\db\Command:

$count = Yii::$app->db->createCommand('SELECT count(...) FROM ... WHERE ...')->queryScalar();