在PHP和排名中汇总行

Question

我正在用php创建学生信息系统，数据库如下所示

**studentId** **Math** **English** **Science** **className**
1                 80        66         85       3p1
2                 75        83         84       3p1
3                 70        88         90       3p1
4                 50        82         50       5p3
5                 88        77         77       3p1
6                 92        97         96       3p1

我想在使用php时只对className 3P1的成员进行排名。当包含以下内容时，下面的sql语句将在phpmyadmin中排名很好

SET @myclassName:=0;
SET @myRank:= 0;
SET @myNextRank:= 0;
SET @myTotals:= 0;   

然而，当我将其转换为php并在php中使用它时，生成的等级是不一致的。每次我重新加载页面时，排名也会发生变化。 我如何包含

SET @myclassName:=0;
SET @myRank:= 0;
SET @myNextRank:= 0;
SET @myTotals:= 0;

在php的查询中。

<?php 

$StudentMarkz = "SELECT X.*,
                        @myRank:=CASE WHEN @myclassName <> className
                                           THEN @myNextRank:=1
                                      WHEN @myTotals <> totals
                                           THEN @myRank:=@myNextRank
                                      ELSE @myRank
                                 END AS Rank,
                        @myclassName:=className AS myclassName,
                        @myTotals:=totals AS myTotals,
                        @myNextRank:=@myNextRank+1 AS myNextRank
                   FROM ( SELECT studentmarkstable.studentId,surname, firstName,
                                 Math,
                                 English,
                                 Science,
                                 SocialStudies,
                                 studentmarkstable.className,
                                 Math + English + Science + SocialStudies AS totals
                            FROM studentmarkstable, student 
                           WHERE student.studentId=studentmarkstable.studentId 
                             AND studentmarkstable.className='3P1' 
                           ORDER BY className ASC,
                                    6 DESC
                        ) X";
$marksQuery = mysql_query($StudentMarkz) or die (mysql_error());

?>

如果我使用$ marksQuery = mysqli_multi_query（$ StudentMarkz）或die（mysql_error（））;我收到了一个错误。

提前谢谢

Answer 1

这是PHP方式（当然你也可以使用mysql方式）。

$sql = "SELECT studentId, Math, Engish, Science FROM table";
$query = mysql_query($sql) or die("Request not successfull!");

$results = array();

while ($result = mysql_fetch_array($adressen_query)){   
  $results[ $result['studentId'] ] = $result['Math'] + $result['Engish'] + $result['Science'];
}
// results now contains all studentIds as Keys and all added result values as value.

// sort descending
$results = arsort( $results );

其他方法：

您可以在表格中添加一个新字段“全部”，并在那里总结所有结果。 （将结果写入表格时，您也可以总结'全部'字段） 然后，您可以使用查询和“ORDER BY”

来访问您的数据

SELECT 'All' FROM table ORDER BY 'All' DESC;

Answer 2

行。这是MySQL的解决方案，因为它可能是PHP脚本编写者中最常用的数据库：

SET @myClass:=0;
SET @myRank:= 0;
SET @myTotals:= 0;
SELECT X.*,
        @myRank:=CASE WHEN @myClass <> class 
                           THEN 1
                      WHEN @myTotals <> totals 
                           THEN @myRank+1
                      ELSE @myRank
                 END AS Rank,
        @myClass:=class AS myClass,
        @myTotals:=totals AS myTotals
  FROM ( SELECT studentId,
                Math,
                English,
                Science,
                Class,
                Math + English + Science AS totals
           FROM studentGrades
          ORDER BY 5 ASC,
                   6 DESC
       ) X

给出：

studentId  Math  English  Science  Class  totals  Rank  myClass  myTotals
2          75    83       84       3p1    242     1     3p1      242
5          88    77       77       3p1    242     1     3p1      242
1          80    66       85       3p1    231     2     3p1      231
6          92    97       96       5p2    285     1     5p2      285
3          70    88       90       5p2    248     2     5p2      248
4          50    82       50       5p2    182     3     5p2      182

在队伍中没有差距

修改

如果您希望在几个同等级别的学生（例如1,2,2,4而不是1,2,2,3）之后保留后续的学生排名职位，请使用以下内容：

SET @myClass:=0;
SET @myRank:= 0;
SET @myNextRank:= 0;
SET @myTotals:= 0;
SELECT X.*,
        @myRank:=CASE WHEN @myClass <> class 
                           THEN @myNextRank:=1
                      WHEN @myTotals <> totals 
                           THEN @myRank:=@myNextRank
                      ELSE @myRank
                 END AS Rank,
        @myClass:=class AS myClass,
        @myTotals:=totals AS myTotals,
        @myNextRank:=@myNextRank+1 AS myNextRank
  FROM ( SELECT studentId,
                Math,
                English,
                Science,
                Class,
                Math + English + Science AS totals
           FROM studentGrades
          ORDER BY 5 ASC,
                   6 DESC
       ) X

给出

studentId  Math  English  Science  Class  totals  Rank  myClass  myTotals  myNextRank
2          75    83       84       3p1    242     1     3p1      242       2
5          88    77       77       3p1    242     1     3p1      242       3
1          80    66       85       3p1    231     3     3p1      231       4
6          92    97       96       5p2    285     1     5p2      285       2
3          70    88       90       5p2    248     2     5p2      248       3
4          50    82       50       5p2    182     3     5p2      182       4

排名差距