这仅仅就是一个内联查询吧
select * form A,B where a.aid = B.name
$db_connect = new PDO("mysql:host=localhost;dbname=db_demo","root","");
$res = $db_connect->query("SELECT B.name from table_A AS A INNER JOIN table_B AS B ON A.id = B.关联字段 WHERE 1");
while($row = $res->fetch()){
print_r($row);
}