cakephp - cakephp 检索数据

Question

我有班级，每个班级都有学生。我想得到一个表，其中包含每个班级的学生人数。在这种情况下如何找到：

$nums = $this->Student->find('count', array('group' => 'Student.Class_id'));

这个结果是不正确的

Answer 1

有几种方法可以归档它：

1. 使用带有 find-all 的虚拟字段

   $this->Student->virtualFields = array('count' => 'COUNT(Student.' . $this->Student->primaryKey .')');
   $this->Student->find("all", array('fields' => 'count', 'group' => 'Student.Class_id'));
   

2. 构建自定义查询

   $this->Student->query("SELECT COUNT(Student.{$this->Student->primaryKey}) as 'count' FROM students Student GROUP BY Student.Class_id");