它不會輸出成功消息中的所有變量

Question

下面我有一個可以成功工作的mysqli查詢;

$courseid = (isset($_POST['courses'])) ? $_POST['courses'] : ''; 
$moduleid = (isset($_POST['moduleid'])) ? $_POST['moduleid'] : ''; 
$moduleno = (isset($_POST['moduleno'])) ? $_POST['moduleno'] : ''; 
$modulename = (isset($_POST['modulename'])) ? $_POST['modulename'] : ''; 

$query = "SELECT cm.CourseId, CourseNo, CourseName, cm.ModuleId 
FROM Course c 
INNER JOIN Course_Module cm 
ON 
c.CourseId = cm.CourseId 
JOIN Module m 
ON 
cm.ModuleId = m.ModuleId 
WHERE cm.CourseId = ? AND cm.ModuleId = ?"; 
// prepare query 
$stmt=$mysqli->prepare($query); 
// You only need to call bind_param once 
$stmt->bind_param("ii", $courseid, $moduleid); 
// execute query 
$stmt->execute(); 
// get result and assign variables (prefix with db) 
$stmt->bind_result($dbCourseId, $dbCourseNo, $dbCourseName, $dbModuleId); 
//get number of rows 
$stmt->store_result(); 
$numrows = $stmt->num_rows(); 

我得到的問題是在我的成功消息。它能夠輸出$moduleno和$modulename變量，但它不會在成功消息中輸出$dbCourseNo和$dbCourseName變量。爲什麼是這樣？

if ($numrows == 1){ 

echo "<span style='color: green'>The following Module has been added into Course:" . $dbCourseNo . " - " . $dbCourseName . ":<br/>" . $moduleno . " - " . $modulename . "</span>"; 

} 

Answer 1

您從未真正獲取過結果，並且我懷疑顯示的變量是過時的操作。

$stmt->execute(); 
// get result and assign variables (prefix with db) 
$stmt->bind_result($dbCourseId, $dbCourseNo, $dbCourseName, $dbModuleId); 

// Can't remember, but you may need to call store_result() before bind_result() ?? 
// maybe not... 
$stmt->store_result(); 
$numrows = $stmt->num_rows(); 
// Fetch the row... 
$stmt->fetch(); 
// Now your variables are populated.