MySQL從多個表中選擇數據-預期幾個子記錄

Question

我有一種錯誤的感覺，那就是表結構有誤，因此對您的幫助將不勝感激。

我有三個桌子

tbl_A (has class and section association) 
    ID
    classid
    sectionid

tbl_B (has subject and class association)
    ID
    classid
    subjectid

tbl_C (has examination and class association)
    ID
    classid
    examid

我需要以以下格式顯示記錄

Class | Section (s) | Subject (s) | Examination (s)
--------------------------------------------------- 
Grade 1 | A, B, C, D | English, Maths, Drawing... | Assessment 1, Assessment 2... 

SQL腳本

SELECT DISTINCT t1.classid, t1.sectionid, t2.subjectid, t3.examid 
    FROM `tbl_A` As t1
JOIN `tbl_B`  t2 ON t1.classid = t2.classid
JOIN `tbl_C`  t3 ON  t1.classid = t3.classid

上面的內容可以通過一個SQL QUERY（帶有join等）來實現，還是需要創建帶有記錄集的單獨SQL來遍歷（例如，Grade 1將具有多個主題，等等）

預先感謝堆積！

Answer 1

SELECT t1.classid, 
       group_concat(t1.sectionid order by t1.sectionid), 
       group_concat(t2.subjectid order by t1.sectionid), 
       group_concat(t3.examid order by t1.sectionid)
    FROM `tbl_A` As t1
JOIN `tbl_B`  t2 ON t1.classid = t2.classid
JOIN `tbl_C`  t3 ON  t1.classid = t3.classid
group by t1.classid