PHP：陣列，具有共同的列約束

Question

的顯示值我有一個多維數組是這樣的：

Array ( 

[0] => Array ([ans_id] => 1 [ans_name] => PHP Hypertext Preprocessor [ques_id] => 1 [right_ans] => Yes [ques_name] => What is the acronym of PHP? [section_id] => 1 [section_name] => PHP) 

[1] => Array ([ans_id] => 2 [ans_name] => Preety Home Page [ques_id] => 1 [right_ans] => No [ques_name] => What is the acronym of PHP? [section_id] => 1 [section_name] => PHP) 

[2] => Array ([ans_id] => 3 [ans_name] => Programmed Hypertext Page [ques_id] => 1 [right_ans] => No [ques_name] => What is the acronym of PHP? [section_id] => 1 [section_name] => PHP) 

[3] => Array ([ans_id] => 4 [ans_name] => Programmed Hypertext Preprocessor [ques_id] => 1 [right_ans] => No [ques_name] => What is the acronym of PHP? [section_id] => 1 [section_name] => PHP)) 

我的表是這樣的：

ans_id ans_name      ques_id    right_ans 

1 PHP Hypertext Preprocessor   1       Yes 

2 Preety Home Page      1       No 

3 Programmed Hypertext Page   1       No 

4 Programmed Hypertext Preprocessor 1       No 

5 Andy Suraski      12       No 

6 Zeev Gutman       12       No 

7 Rasmus Lerdorf      12       Yes 

8 Perl        12       No 

我想檢索套的答案常見問題編號

即一套Ques_id='1'的所有答案，ques_id='12'等的所有答案的第二套等

我應該使用此代碼：

foreach($all_ans_cat as $r) 
{      
    echo $r['ans_id']." ".$r['ans_name']."<br>"; 
} 

這是檢索所有存在於表作爲一組，又在第二盤被顯示的值相同的值。

Answer 1

選擇通過ques_id排序的所有答案，並與結構產生陣列所需

$questions = array(); 
$prevQuestionId = null; 
foreach ($all_ans_cat as $r) { 
    if ($r['ques_id'] !== $prevQuestionId) { 
     $questions[] = array(); 
    } 
    $questions[sizeof($questions)-1][] = $r; 
    $prevQuestionId = $r['ques_id']; 
} 

結果數組將是：

0: 
    - [ans1, ques1] 
    - [ans2, ques1] 
    ... 
1: 
    - [ans5, ques13] 
    - [ans6, ques13] 
    ... 
... 

Answer 2

您可以使用與A組查詢和聚合函數

看看

http://www.w3schools.com/sql/sql_groupby.asp