How to Perform Join Queries in ThinkPHP: Native SQL, join() and table() Methods

ThinkPHP supports multi-table join queries through three main approaches: writing raw SQL, using the join() method, and using the table() method. The following examples illustrate each technique.

1. Native query example:

<code>$Model = new Model();
$sql = 'select a.id,a.title,b.content from think_test1 as a, think_test2 as b where a.id=b.id ' . $map . ' order by a.id ' . $sort . ' limit ' . $p->firstRow . ',' . $p->listRows;
$voList = $Model->query($sql);
</code>

2. join() method example:

<code>$user = new Model('user');
$list = $user->join('RIGHT JOIN user_profile ON user_stats.id = user_profile.typeid');
</code>

3. Complex join using multiple join() calls:

<code>$user = M('user');
$b_user = M('b_user');
$c_user = M('c_user');
$list = $user->alias('user')
    ->where('user.user_type=1')
    ->join('b_user as b on b.b_userid = user.user_id')
    ->join('c_user as c on c.c_userid = b.b_userid')
    ->order('b.user_time')
    ->select();
// $user 表的 user_id 等于 $b_user 表的 b_userid；
// $c_user 表的 c_userid 等于 $b_user 表的 b_userid；
</code>

4. table() method example:

<code>$list = $user->table('user_status stats, user_profile profile')
    ->where('stats.id = profile.typeid')
    ->field('stats.id as id, stats.display as display, profile.title as title, profile.content as content')
    ->order('stats.id desc')
    ->select();
</code>

These snippets show how to perform join queries, set aliases, apply conditions, select specific fields, order results, and limit output within ThinkPHP.