Question

我有两张桌子：

events     event_follows
-------    -------------
id         id
title      user_id
content    event_id
user_id

我需要获取某些user_id的所有事件，事件数量，获取此用户所遵循的所有事件并获取所有事件和所遵循的计数。真的，我不知道在1个查询中如何正确执行此操作。

Answer 1

我可以从你的问题中理解，我只能想到这个解决方案：

$query = "select e.*, count(e.*), ef.*, count(ef.*) from events e join event_follows ef on ef.user_id = e.user_id where e.user_id = '$my_id' ";
$data['info'] = $this->db->query($query)->result_array();

//Then, you can use php's echo "<pre>", print_r() and die() functions 
//to test the result:

echo "<pre>";
print_r(data['info']);
die();

Answer 2

我已经做出了一些解决方案。但不幸的是，它比1个查询更复杂：

    // Fetch all events which was joined by user
    $this->db->select('event_id')
             ->from('event_follows')
             ->where('user_id', $id);

    $query1 = $this->db->get(); 
    $result = $query1->result_array();   

    // Drop keys
    $joined_events = array();       
    foreach($result as $row)
    {
        array_push($joined_events, $row["event_id"]);   
    }

    // Fetch all events
    $this->db->select('events.*, COUNT(event_follows.id) as followers')
             ->from('events')
             ->where('events.user_id', $id)
             ->or_where_in('events.id', $joined_events);
    $this->db->join('event_follows', 'event_follows.event_id = events.id', 'left')
             ->group_by('event_follows.event_id');

    $query2 = $this->db->get();

Codeigniter：2个表的复杂查询

2 个答案: