php - MySql getting sum: one table contains values, in other tables is rest of data -

i have 3 tables.

• first table(items) has: item_id, item_name, , item_value.

• second table(handouts) contains: handout_id, handout_item_id, month, vol_id, receiver_name.

• third table(volunteer) contains volunteer_id, volunteer_name

i need output monthly sum of items value, per volunteer selected month. here have far(what stuck :-s):

    function mesec_svi(){ global $konekcija; $mes=$_get['mes'];  $query= "select distinct vol_id handouts mes = {$mes} "; $mesec_svi = mysqli_query($konekcija, $query);  potvrda_query($mesec_svi);   while($mesec_svi_lista=mysqli_fetch_assoc($mesec_svi)){   $volid= $mesec_svi_lista["vol_id"];        echo $volid.' ';      $query1= "select handout_item_id handouts vol_id =  {$volid}     ,  mes = {$mes}";         $mesec_svi_o = mysqli_query($konekcija, $query1);     potvrda_query($mesec_svi_o);  while($mesec_svi_olista=mysqli_fetch_assoc($mesec_svi_o)){   $itemid= $mesec_svi_olista["handout_item_id"];   $query2= "select item_value items itemid = {$itemid}";    $pr_svi_o = mysqli_query($konekcija, $query2);     potvrda_query($pr_svi_o);    while($pr_svi_olista=mysqli_fetch_assoc($pr_svi_o)){         $pr= $pr_svi_olista["item_value"];         echo '</br>'.$pr.'</br>';}    }       }  } 

this displaying results:

1  200 100 50 2 50 50 100 

where 1 , 2 volunteer ids , other numbers items value. need values summed.

1 350 2 200 

i tried sum() , array_sum no luck.

try inner join. query -

select sum(item_value) sum_item handouts  inner join items on items.itemid = handouts.handout_item_id vol_id = {$volid} ,  mes = {$mes} group items.itemid 

and loop through -

while($mesec_svi_olista=mysqli_fetch_assoc($mesec_svi_o)){     echo $mesec_svi_olista['sum_item'].'<br>'; }