每年级别的男性和女性总数，然后全部使用codeigniter

Question

我对每年级别的男女总和以及所有男女的总和有疑问。例如，我有 4 个学生，在 7 年级（年级）我有一个女学生和一个男学生，在 8 年级我有一个男学生，在 8 年级我有一个男学生，但问题也算在相反的情况下性别。我也有 ORDER BY ASC 或 DESC 的问题，我不知道为什么。

这是图片->

这是我的模态：

  function gendercountz(){
  
        $query = $this->db->query('select Sex
     , COUNT( case when Sex = "Male"
                 then 1 else 0 end ) as male
     , COUNT( case when Sex = "Female"
                 then 1 else 0 end ) as female
  from studentinformation');
            return $query->result();
        
    }
   function gendercountzx(){
      
        $querys = $this->db->query('SELECT Yearlevel, COUNT(*) AS studentcount, COUNT(case when Sex = "Male" then 1 else 0 end) AS malecount, COUNT(case when Sex = "Female" then 1 else 0 end) AS femalecount FROM studentinformation GROUP BY Yearlevel ORDER BY Yearlevel DESC');
            return $querys->result();
        
    }

这是我的看法：

<table class=" table table-hover ">
            
               
		         <thead>
                             <tr>
                             
                                 <th class="text-center">Year Level</th>
                                   <th class="text-center">Male</th>
                                   <th class="text-center">Female</th>
                                   <th class="text-center">Total</th>
                                  
                                   
                           </tr>
                          
                             <?php 
    foreach ($this->model_adminlogin->gendercountzx() as $ewa){ ?>
                           <tr>
                  
                   
             
                
               <td >   <h5 class="text-center"> <?php echo $ewa->Yearlevel?></h5>
   
   
		   </td>
                   <td class="text-center"><?php echo $ewa->malecount?></td>
                              <td class="text-center"><?php echo $ewa->femalecount?></td>
                  
                   <td class="text-center"><?php echo $ewa->studentcount?></td>
                   
                        
                             
         </tr>
        
        <?php 
     }
    ?>  
                
				
			
         <tr>
                       
             <td class="text-center"><b>Total</b></td>
                <?php 
    foreach ($this->model_adminlogin->gendercountz() as $ewa){ ?>
                <td class="text-center"> <?php echo $ewa->male?></td>
                 <td class="text-center"> <?php echo $ewa->female?></td>
                 
                   <?php 
     }
    ?>  
                  <td class="text-center"><?php echo  $this->db->count_all('studentinformation'); ?></td>
         </tr>
                           
                           </table>

Answer 1

假设你有Yearlevel 作为int 数据类型......那么你可以使用

function gendercountzx()
{
    $query = $this->db->query('SELECT CONCAT("Grade ", Yearlevel) as Yearlevel, COUNT(*) AS studentcount, sum(case when Sex = "Male" then 1 else 0 end) AS malecount, sum(case when Sex = "Female" then 1 else 0 end) AS femalecount FROM studentinformation GROUP BY Yearlevel ORDER BY Yearlevel DESC'); 
    return $querys->result();
}