Days of Stay counter with php

Question

I'm a little stuck on my homework. I'm doing a hospital days counter,

The time, day, month and year of entry are recorded, as well as a possible exit with day month and year.

The program needs to calculate the days of stay each month and charge them per month whether the month of stay has been completed or not.

I am very very stuck I hope you can help me, I am just learning.

Is in scriptcase php and is oriented to an event:

    $f = {folio};

//fechasdeentrada

$check_sql3 = "SELECT id FROM HabitaAct WHERE folio = ".$f;
sc_lookup(ds_3, $check_sql3 );
$id1 = {ds_3[0][0]}; 
$check_sql4 = "SELECT diae FROM HabitaAct WHERE id = '".$id1."' ";
sc_lookup(ds_4, $check_sql4 );
$diae = {ds_4[0][0]}; // day
$check_sql2 = "SELECT mese FROM HabitaAct WHERE id = '".$id1."' ";
sc_lookup(ds_2, $check_sql2 );
$mese = {ds_2[0][0]}; // month
$check_sql5 = "SELECT Ane FROM HabitaAct WHERE id = '".$id1."' ";
sc_lookup(ds_5, $check_sql5 );
$Ane = {ds_5[0][0]}; // year
$check_sql6 = "SELECT tieme FROM HabitaAct WHERE id = '".$id1."' ";
sc_lookup(ds_6, $check_sql6 );
$tieme = {ds_6[0][0]}; // time

//exit date

$check_sql7 = "SELECT diaS FROM HabitaAct WHERE id = '".$id1."' ";
sc_lookup(ds_7, $check_sql7 );
$diaS = {ds_7[0][0]}; //day
$check_sql8 = "SELECT mesS FROM HabitaAct WHERE id = '".$id1."' ";
sc_lookup(ds_8, $check_sql8 );
$mesS = {ds_8[0][0]}; //month
$check_sql9 = "SELECT AnS FROM HabitaAct WHERE id = '".$id1."' ";
sc_lookup(ds_9, $check_sql9 );
$AnS = {ds_9[0][0]}; // year

$dientr = $diae;
$anac = $Ane;
$vd =$diae;
$ma = $mese;
$aa=  $Ane;
$an = $Ane; 
$limanu = 12;   


if( $mesS == $mese ){
    
    if($AnS==$Ane){
        
        $dmeig = $diaS - $diae;     
        
        echo $dmeig;
        
        if($diae=0){
            $diae=1;
        }
        
        echo $diae;
        
    }

}else{

    for (; ; ) {
        
        if( $ma == 1 ){ $limitedemes= 31; }
        if( $ma == 2 ){ $limitedemes= 28; }
        if( $ma == 3 ){ $limitedemes= 31; }
        if( $ma == 4 ){ $limitedemes= 30;}
        if( $ma == 5 ){ $limitedemes= 31;}
        if( $ma == 6 ){$limitedemes= 30;}
        if( $ma == 7 ){ $limitedemes= 31;}
        if( $ma == 8 ){ $limitedemes= 31;}
        if( $ma == 9 ){ $limitedemes=  30;}
        if( $ma == 10 ){ $limitedemes= 31;}
        if( $ma == 11 ){ $limitedemes= 30;}
        if( $ma == 12 ){ $limitedemes=31;}      
        
        if($ma ==  $mesS ){
            if( $aa == $AnS ){
                $limanu = $mesS;
                $ma = 1;
            }else{
                $limanu = $mesS;
            }
        }else{
            $limanu = 12;
        }       
        $contadordedias = $limitedemes - $vd;
        
        echo "<br> ".$vd." dias totales   ".$contadordedias; 
        echo "<br> mes actual ".$ma; 
        $man = $ma;
        $ma = $man+1;
        $vd = 0;
        echo "<br> set 0  ".$vd; 
        
        if ($ma > $limanu ||  $ma = 12 ) {
            
            $ma = 1;
            $an = $aa + 1;
            
            echo "<br> año ".$aa;
            
            if ($aa > $AnS ) {
                
                if($ma = $mesS ){
                    echo "dias mes final".$diaS;        
                    break;
                }       
            }
        }                               
    }               
}