array and adding

Richardtagger

i have lots of values in my sql table, i need to collect all the values from each row and retireve them in an array, then find the average of this array.

<td width="122"><strong>Average Bid:</strong> <?php  $getprices = mysql_query("SELECT * FROM bids WHERE project='$id'"); 

 function add_array($array) 
 { 
 for( $i = 0; $i < count( $array ); $i++ ) 
 { 
  $total_array = intval($total_array) + intval($array[$i] ); 
 } 

 return $total_array; 
 } 
 while($result = mysql_fetch_array($getprices)) { 
 $bid3 = $result['bid']; 
 echo $bid3;
 } 
?></td>

can anyone see the problem? thanx

kburger

The first thing I see is that you're never calling your add_array() function. You only defined it.

Richardtagger

woops lol, i took that out as it gave error and forgot to put it back in,heh.

ok if i add

 echo add_array($bid3);

the values come out as 12, the two values in the array are 100 and 245, if i just get the array it comes out as 100245, when using the function it comes out as 12. the first number in each part of the array... :S

kburger

I think I'd let MySQL do the averaging for you. One pitfall is to watch out for any NULL values. I don't think they'll be figured into the average.

SELECT AVG(bid) FROM bids WHERE project='$id';

Richardtagger

now im not sure wqhat to do with the mysql result output?

$getprices = mysql_query("SELECT AVG(bid) FROM bids WHERE project='$id'"); 


 $bid3 = mysql_result($getprices,0,"bid");
 echo $bid3;

that isnt right, what is? cheers.

kburger

This should do it:

<td width="122"><strong>Average Bid:</strong> <?php  

$getprices = mysql_query("SELECT AVG(bid) FROM bids WHERE project='$id'"); 
list($avg) = mysql_fetch_array($getprices);
echo $avg;
?></td>

Richardtagger

thanks, youre a star.

kburger

No problem. You also might want to check out number_format() to format the average.

Richardtagger

yeh im rounding it prlly witrh round() function heh. ty again.

bradgrafelman

Also, just a note on MySQL.

You can alias columns (or fake columns, as in this case) with a name so they are easy to call, like so:

$getprices = mysql_query("SELECT AVG(bid) AS average FROM bids WHERE project='$id'");  


 $bid3 = mysql_result($getprices,0,"average"); 
 echo $bid3;

Just a little tidbit of info for the future.