$arr[] = array('id'=>22533,'teacher'=>1275,'year'=>'2020','coursetype'=>5,'teachhour'=>8);
$arr[] = array('id'=>22534,'teacher'=>1275,'year'=>'2019','coursetype'=>3,'teachhour'=>6);
$arr[] = array('id'=>22532,'teacher'=>1275,'year'=>'2019','coursetype'=>5,'teachhour'=>8);
$arr[] = array('id'=>22535,'teacher'=>1275,'year'=>'2019','coursetype'=>5,'teachhour'=>7);
$arr[] = array('id'=>22536,'teacher'=>1275,'year'=>'2019','coursetype'=>5,'teachhour'=>8);
 
//怎么判断当teacher year coursetype 相同时让teachhour相加变成一条数据
$paramArr=array(); 
foreach($arr as $key => $value){
        foreach($arr as $k => $val){
            if($val['teacher'] == $value['teacher'] && $val['year'] == $value['year'] && $val['coursetype'] == $value['coursetype']){
                $KeyXiaoLL = $value['teacher'].'-'.$value['year'].'-'.$value['coursetype'];
                @$paramArr[$KeyXiaoLL]['total_hour'] = $val['teachhour']+$paramArr[$KeyXiaoLL]['total_hour'];
                unset($arr[$k]);
            }
    }  
} 
//最终数组 $ArrXiaoLL
$ArrXiaoLL = array();
foreach($paramArr as $key=>$val){ 
    
    if($val['total_hour'] <= 0){
        continue;
    } 
    $param = explode('-',$key); 
    $param['teacher'] =  $param[0];
    $param['year'] =  $param[1];
    $param['coursetype'] =  $param[2];
    unset($param[0]);
    unset($param[1]);
    unset($param[2]);
    if(is_array($param)){
         $param['total_hour'] = $val['total_hour'];
    }
     
    $ArrXiaoLL[] = $param;
}

echo '<pre>';
print_r($ArrXiaoLL); 
exit;