使用PHP縮短重複的1400行MySQL UNION查詢

Question

我有一個1275字段寬的MYSQL表。表格中的每一行都代表一個班級的學生，每個學生有17個字段，每個班級X可達75個學生，因此17個X 75 = 1275個字段。

我設計了一個SQL UNION查詢，成功地將學生拉入另一個表，每個學生在一行上。

現在，我想使用這個UNION查詢作爲PHP程序的一部分。我已經將查詢「導入」到PHP中了。但是，沒有辦法使用PHP來縮短SQL查詢嗎？無恥的，這是我的代碼：

$sql = " 
    INSERT INTO $t_mem2 
    SELECT localcourse 
     , statecourse 
     , coursetitle 
     , semester 
     , section 
     , teachercode 
     , teachername 
     , meetingcode 
     , classpop 
     , student_id_01 AS student_id 
     ,  sex_01 AS sex 
     ,  dob_01 AS dob 
     ,  grade_01 AS grade 
     ,  ethnic_01 AS ethnic 
     , last_name_01 AS last_name 
     , first_name_01 AS first_name 
     , $c_sch  AS sch_code 
    FROM $t_mem1 
    UNION 
    SELECT localcourse 
     , statecourse 
     , coursetitle 
     , semester 
     , section 
     , teachercode 
     , teachername 
     , meetingcode 
     , classpop 
     , student_id_02 AS student_id 
     ,  sex_02 AS sex 
     ,  dob_02 AS dob 
     ,  grade_02 AS grade 
     ,  ethnic_02 AS ethnic 
     , last_name_02 AS last_name 
     , first_name_02 AS first_name 
     , $c_sch  AS sch_code 
    FROM $t_mem1 
    UNION 
    SELECT localcourse 
     , statecourse 
     , coursetitle 
<...snip..............................> 
    , teachername 
    , meetingcode 
    , classpop 
    , student_id_75 AS student_id 
    ,  sex_75 AS sex 
    ,  dob_75 AS dob 
    ,  grade_75 AS grade 
    ,  ethnic_75 AS ethnic 
    , last_name_75 AS last_name 
    , first_name_75 AS first_name 
    , $c_sch  AS sch_code 
    FROM $t_mem1 
ORDER 
    BY localcourse 
    , statecourse 
    , semester 
    , section 
    , teachername 
    , meetingcode 
    , last_name 
    , first_name" ; 

Answer 1

首先更換01 .. 75，這個查詢表明你的數據庫架構是非常非常差。

這且不說，是的，你可以縮短與PHP查詢：

$query = "INSERT INTO $t_mem2 "; 
for ($i = 1; $i <= 75; $i++) { 
    if ($i > 1) { 
     $query .= ' UNION '; 
    } 
    $s = "$i"; 
    if ($i < 10) { 
     $s = '0'.$s; 
    } 
    $query .= "SELECT localcourse 
     , statecourse 
     , coursetitle 
     , semester 
     , section 
     , teachercode 
     , teachername 
     , meetingcode 
     , classpop 
     , student_id_{$s} AS student_id 
     ,  sex_{$s} AS sex 
     ,  dob_{$s} AS dob 
     ,  grade_{$s} AS grade 
     ,  ethnic_{$s} AS ethnic 
     , last_name_{$s} AS last_name 
     , first_name_{$s} AS first_name 
     , $c_sch  AS sch_code FROM $t_mem1"; 
} 
$query .= " ORDER 
BY localcourse 
, statecourse 
, semester 
, section 
, teachername 
, meetingcode 
, last_name 
, first_name" ; 

這會「縮短查詢」由PHP代碼生成它。另一方面，如果您希望查詢，因爲它會縮短數據庫，這也是可能的;只需修改上面的循環，在每次迭代中重新開始$query，並將所有結果一起放入一個數組中。您最終將完成75個查詢，PHP將執行UNION。

Answer 2

讓我成爲第一個說OMG的人！

其次，開始閱讀關於規範化：http://en.wikipedia.org/wiki/Database_normalization

三：使用一個循環，並與printf('%02d', $i)

Answer 3

我打電話給WoLpH的OMG，然後提出一個WTF。

爲了更多地解釋「正常化」的含義，您希望在這裏至少有兩個表格：一個用於課程，一個用於學生（可能還有一個用於教師）。所有與一些領域進入students表，teachername和teachercode（可能帶有id）進入teachers表，一切進入courses表，有一些新的領域一起：teacher_id（或teachercode）和student_id，和最好是它自己的AUTOINCREMENT ed id。然後，當你想獲得類似的70KB查詢的結果，你這樣做：

SELECT C.id AS course_id 
    , C.localcourse 
    , C.statecourse 
    , C.coursetitle 
    , C.semester 
    , C.section 
    , T.teachercode 
    , T.teachername 
    , C.meetingcode 
    , C.classpop 
    , C.student_id 
    , S.sex 
    , S.dob 
    , S.grade 
    , S.ethnic 
    , S.last_name 
    , S.first_name 
FROM courses C 
JOIN students S ON C.student_id = S.id 
JOIN teachers T ON C.teacher_id = T.id 

而且，你也許並不需要classpop，你可以用SELECT COUNT(C.student_id) AS classpop ... GROUP BY C.id得到它。