將限制只顯示學生 ID 為 # 1，不包括其他一切內容

Question

`` $query = "SELECT t1.ID,t1.student_id, t1.Subject, t1.1st_Grading, t1.2nd_Grading, t1.3rd_Grading, t1.4th_Grading, t1.Status, SUM(t1.1st_Grading t1.2rd_Grading, t1.Status, SUM(t1.1st_Grading t1.2rd_Grading, t1.31. 4th_Grading) / 4 as Average FROM grading_system t1 LEFT JOIN studentdata t2 ON t1.student_Id = t2.ID GROUP BY t1.ID ";

這是這段程式碼的結果，如果你看到url中的紅色箭頭，它是一個學生# 1，裡面還包括學生# 2項

![](https://i.stack.imgur.com/5wS7h.png)

Answer 1

當使用者點擊學生 ID 為 1 的連結時，將會取得該連結中的參數 id，然後在 PHP 中使用 global 變數 $_GET['id'] 來查詢資料庫，並在查詢中使用 WHERE 子句。

// Get the student ID from the URL parameter
$studentId = isset($_GET['id']) ? $_GET['id'] : null;


// Prepare the SQL query with the WHERE clause to fetch the specific student's data
$query = "SELECT t1.ID, t1.student_id, t1.Subject, t1.1st_Grading, t1.2nd_Grading, t1.3rd_Grading, t1.4th_Grading, t1.Status, 
          SUM(t1.1st_Grading + t1.2nd_Grading + t1.3rd_Grading + t1.4th_Grading) / 4 as Average 
          FROM grading_system t1 
          LEFT JOIN studentdata t2 ON t1.student_Id = t2.ID 
          WHERE t1.student_id = $studentId
          GROUP BY t1.ID";