Double Join Select

Question

Three tables Project, Users, Issues.

• Project table columns: p_id,name,...
• Users table columns: u_id username...
• Issues table columns: i_id i_name...

Relations:

• Project has many Users - 1..*
• Project has many Users - 1..*
• Project has many Issues - 1..*
• Users has many Issues - 1..*

What I want to do:

In Yii framework logic: Select Project with all it's users, these users has to have only Issues of the selected Project.

In tables logic: Select Issues of certain project AND user.

What sql code I want to mimic:

SELECT Issue.i_name FROM Issue Join Project on Issue.i_id = Project.p_id Join User on Issue.i_id User.u_id

What I want to do in Yii:

//get Project
$model = Project::model()->findByPk( $p_id );
//get Project's users
$users = $model->users;
//get each of users issues of selected project
foreach( $users as $user ) 
    $issues = $user->issues;

Answer 1

To solve this you have to use through in your ralations method.

Project model relations method should look like this:

public function relations()
    {
            return array(
                'users' => array(self::MANY_MANY, 'User', 'tbl_project_user_assignment(project_id, user_id)'),
                //'issues' => array(self::HAS_MANY, 'Issue', 'project_id'),
                'issues' => array(self::HAS_MANY,'Issue',array('id'=>'owner_id'),'through'=>'users'),

                'columns' => array(self::MANY_MANY, 'Column', 'tbl_project_rel_column(p_id,c_id)'),
            );
    }

Now in action select project, it's users and users's posts(or in my case issues) of selected project:

 $project = Project::model()->with('users','issues')->findByPk(1);


            $users = $project->users;

            foreach($users as $user) {
                echo $user->username."<br/>";
            }

            $issues = $project->issues;

            foreach($issues as $issue) {
                echo $issue->name."<br/>";
            }