Codeigniter - Active record - sql - complex join

问题

I have a function that retrieves all tags from a table:

function global_popular_tags() {
    $this->db->select('tags.*, COUNT(tags.id) AS count');
    $this->db->from('tags');
    $this->db->join('tags_to_work', 'tags.id = tags_to_work.tag_id');
    $this->db->group_by('tags.id');
    $this->db->order_by('count', 'desc'); 
    $query = $this->db->get()->result_array();
    return $query;
}

I have another table called 'work'. The 'work' table has a 'draft' column with values of either 1 or 0. I want the COUNT(tags.id) to take into account whether the work with the specific tag is in draft mode (1) or not.

Say there are 10 pieces of work tagged with, for example, 'design'. The COUNT will be 10. But 2 of these pieces of work are in draft mode, so the COUNT should really be 8. How do I manage this?

回答1:

Try changing:

$this->db->from('tags');
$this->db->join('tags_to_work', 'tags.id = tags_to_work.tag_id');

To:

$this->db->from('tags, work');
$this->db->join('tags_to_work', 'tags.id=tags_to_work.tag_id AND work.id=tags_to_work.work_id');

And Adding:

$this->db->where('work.drafts', 0);

回答2:

You can use pure sql instead of using the active record class, I myself are working with CI for over 2 years and most of the time I am avoiding the active record class, cause straight sql is much easier to debug and write complex queries. This is how i would use it.

$sql = "SELECT...your sql here";
$q = $this->db->query($sql);
...
//Do something with your query here

来源：https://stackoverflow.com/questions/5195627/codeigniter-active-record-sql-complex-join

标签

php

sql

codeigniter

activerecord