如何比较数据库中的两个数组并获得差异

Im having a trouble about arrays in php, can anyone help me on how to compare two arrays in the database and get their difference. And the difference will be stored in the database. Im new in php and im so confused dealing with array functions.

我在php中有关于数组的问题,任何人都可以帮助我如何比较数据库中的两个数组并获得它们的不同。差异将存储在数据库中。我是新的PHP和我很困惑处理数组函数。

My codes looks like:

我的代码如下:

This is where i get my arrays:

这是我得到我的数组的地方:

$year = $_POST['year'];
$course = $_POST['Course'];
$block = $_POST['block'];

$cheetah = mysql_query("SELECT stud_valid_nos FROM exam_students WHERE stud_subject_id = '$subject_id'")or die(mysql_error());  
while($validnos = mysql_fetch_array($cheetah)){
    $nos = $validnos['stud_valid_nos'];
    }
$tiger = mysql_query("SELECT sec_id_num FROM exam_sections WHERE sec_year = '$year' AND sec_course = '$course' AND sec_block = '$block'")or die(mysql_error()); 
while($idnum = mysql_fetch_array($tiger)){
    $id = $idnum['stud_valid_nos'];
    }

if($nos ???? $id){ ///this is where the arrays being compared.

inserts only the difference

}

else{

inserts the full array in the database
}

Sorry for my bad english :) Godbless!

抱歉我的英语不好:) Godbless!

Ive decided not to use array anymore, maybe some of you has a piont, so ive reorganize my codes but its still not working. How can i add student numbers in my database with no duplicates?

我决定不再使用数组,也许你们中有些人有一个piont,所以我重新组织我的代码,但它仍然无法正常工作。如何在我的数据库中添加学生编号而不重复?

here is my new code:

这是我的新代码:

$cheetah = mysql_query("SELECT stud_valid_nos FROM exam_students WHERE stud_subject_id = '$subject_id'")or die(mysql_error());  
if(mysql_num_rows($cheetah)>0){

while($validnos = mysql_fetch_array($cheetah)){
    $nos = $validnos['stud_valid_nos'];

    $tiger = mysql_query("SELECT sec_id_num,sec_email FROM exam_sections WHERE sec_id_num <> '$nos' AND sec_year = '$year' AND sec_course = '$course' AND sec_block = '$block'")or die(mysql_error());
while($idnum = mysql_fetch_assoc($tiger)){
    $id = $idnum['sec_id_num'];
    $email = $idnum['sec_email'];


    $insert = mysql_query("INSERT INTO exam_students (stud_valid_nos, stud_email, stud_subject_id, stud_group_id ) VALUES ('$id','$email','$subject_id','$examinergroupid')")or die(mysql_error());
    $last = mysql_insert_id();
    $password = genRandomString();
    $rawr = mysql_query("INSERT INTO exam_passwords (pass_user_id,pass_password,pass_subject_id,pass_exam_id) VALUES ('$last','$password', '$subject_id', 0)")or die(mysql_error());

    }

    }

maybe I should use the NOT IN or IS NULL functions in mysql_query? anyone who can show me on how to get rid of my problem? thanks :)

也许我应该在mysql_query中使用NOT IN或IS NULL函数?有谁可以告诉我如何摆脱我的问题?谢谢 :)

3 个解决方案

#1

$diff = array_diff($nos, $id);
if (count($diff)) {
     // insert diff
} else {
     // insert full array
}

http://php.net/manual/en/function.array-diff.php

#2

Be careful - think about what you really want to get:

小心 - 想想你真正想要得到的东西:

Look at this example:

看看这个例子:

$arr1 = array("a", "b", "c", "d");
$arr2 = array("c", "d", "e", "f");

$diff1 = array_diff($arr1, $arr2);
$diff2 = array_diff($arr2, $arr1);

$diff1 contains "a" and "b" because it will return what is in the $arr1 and not in $arr2

$ diff1包含“a”和“b”,因为它将返回$ arr1中的内容,而不是$ arr2中的内容

$diff2 contains "e" and "f" because it will return what is in the $arr2 and not in $arr1

$ diff2包含“e”和“f”,因为它将返回$ arr2中的内容,而不是$ arr1中的内容

If you want to get full diff you have to merge $diff1 and $diff2 together:

如果你想获得完全差异,你必须将$ diff1和$ diff2合并在一起:

$f_diff = array_merge($diff1, $diff2);

Then:

if (count($f_diff)) {
    //insert difference
}
else {
    //insert all
}

#3

Just combine both conditions like this ?:

只需结合这两个条件?:

INSERT INTO exam_sections
VALUES (SELECT * 
        FROM exam_sections
        WHERE sec_year = '$year' AND sec_course = '$course' AND sec_block = '$block'
        AND  stud_subject_id != '$subject_id'
        )

Columns and Values for the INSERT need to be arranged properly !

INSERT的列和值需要正确排列!

#1

$diff = array_diff($nos, $id);
if (count($diff)) {
     // insert diff
} else {
     // insert full array
}