array structure problem -- probably elementary

[stevieontario]

Afternoon Freaks,

 

I'm trying to add up certain variables inside an array, and keep going around in circles. The array is the result of a mysql SELECT query. I select the contents of a database table, then extract them in php using the following code:

while ( $row = mysql_fetch_assoc($result)) {	
		extract($row);
}

 

var_dump($row) outputs the following:

Array

(

    [var1] => 1193

    [var2] => 799

    [var3] => 805

    [var4] => 0.992547

    [var5] => 2010-12-20

    [var6] => 20

)

Array

(

    [var1] => 1193

    [var2] => 725

    [var3] => 725

    [var4] => 1

    [var5] => 2010-12-20

    [var6] => 20

)

Array

(

    [var1] => 1193

    [var2] => 818

    [var3] => 850

    [var4] => 0.962353

    [var5] => 2010-12-20

    [var6] => 20

)

Array

(

    [var1] => 1194

    [var2] => 819

    [var3] => 860

    [var4] => 0.952326

    [var5] => 2010-12-20

    [var6] => 21

)

Array

(

    [var1] => 1194

    [var2] => 829

    [var3] => 870

    [var4] => 0.952874

    [var5] => 2010-12-20

    [var6] => 21

)

 

Array

(

    [var1] => 1194

    [var2] => 831

    [var3] => 870

    [var4] => 0.952874

    [var5] => 2010-12-20

    [var6] => 21

)

 

What I want is to add up all the var2 values for each var1.

 

e.g., in the case of var1=1193, this would be 799 + 725+ 818.

 

Of course, there are nearly 2,000 var1s (each one with multiple var2s), and I want my computer to do all the work.

 

So I'm trying to isolate each var1 so I can figure out some loop to do this operation. I've tried a bunch of funny little tricks with min(), but keep going in circles.

 

Any ideas?

[Zane]

There is no reason to use extract.. 

 

The best route in storing the data would be something like this

while($row =  mysql_fetch_array())  $data[] = $row;

That way you have one variable full of arrays.

 

Now you can do something like this

foreach($data as $index=>$value) {
   $data[$index]['var1'] += $data[$index]['var2'];
}

 

That most likely WILL NOT work, but I hope you get the idea.

[AbraCadaver]

You would probably be better off using SUM() and GROUP BY in your query.

[stevieontario]

Zanus, thanks. I'll study your suggestion, though I don't see the difference between the result I get from my extract and your first statement. You correctly assumed that var1 is an auto-incremented field, and I was thinking along the lines of your foreach statement. Let me fiddle around with it and see what happens.

 

Abra, thanks as well. I tried using a subquery, but it wouldn't let me get more than one group of var1s ("subquery returns more than one row").

[stevieontario]

You see, my problem is I have no idea what I'm doing. I got stuck on the subquery (for whatever reason) and that was what had me hung up. So I took it out and grouped by var1 and PRESTO! Problem solved!

 

Thanks everyone!