php加入多個表的查詢

Question

任何人都可以告訴我如何獲得project_title，project_id，level_of_want和selection_id的值。當我提交這個我得到沒有數據庫選擇錯誤。

$query_Name = "SELECT u.Student_Surname, u.Student_Forename, p2.Project_Title,  
p2.Project_id, s.level_of_want, s.selection_id 
FROM users u 
INNER JOIN projects p2 ON u.id = p2.Project_Lecturer 
INNER JOIN selection s ON p2.Project_id = s.id_project 
INNER JOIN users u2 ON s.student_id = u2.id 
WHERE u2.Username = ".$_SESSION['MM_Username']." ORDER BY selection_id ASC" ; 
$Name = mysql_query($query_Name, $projectsite) or die(mysql_error()); 
$row_Name = mysql_fetch_assoc($Name); 
$totalRows_Name = mysql_num_rows($Name); 

Answer 1

連接到MySQL服務器上之後，你應該明確地選擇數據庫使用mysql_select_db功能

Answer 2

mysql_select_db($bd); 

我們需要看你怎麼連