mysql data math operation

sebatm

hi, i'm currently learning php and i need some help.

i want to make some math operations with some data from an mysql table, and printing the result.

the operation is simple [x-(x-1)]*y but i didn't manage to write it properly.
there are two columns
x - the current read number from col2
(x-1) - the previous read number from col2
y - number from the same row as the (x-1) number, but from a diferent column (col1).

i made the mysql connection and the printing, i got in trouble with this part.

can someone help?

thank you,

Weedpacket

Posting the relevant part of your code might help.

sebatm

sorry.

here is the code for what i tried to do:

	for($temp[$i] = mysql_query('SELECT nrcont FROM con_apa_rece'); ;$temp[$i++]) 
	{
	$pret= mysql_query('SELECT pret FROM con_apa_rece');
	 ($valoare=($temp[$i]['nrcont']-$temp[$i-1]['nrcont'])*$pret['pret']);
		if($valoare<'0')
			echo "Nu exista inreg anterioara";
		else
			echo $valoare;
	}

praveenp

I guess below code may be useful for you.

$sql = "SELECT nrcont, pret FROM con_apa_rece";
$query = mysql_query($sql);
$rowCount = mysql_num_rows($query);
if($rowCount > 0){
$result = mysql_fetch_assoc($query);
$prevCol12Value = $result['col2'];
$prevPretValue = $result['col2'];
if($rowCount > 1){
while($result = mysql_fetch_assoc($query)){
$valoare = ($result['col2'] - $prevCol12Value) $prevPretValue;
$prevCol12Value = $result['col2'];
$prevPretValue = $result['col2'];
echo $valoare; // you can define how ever you want.
}
}
else
{
$valoare = ($prevCol12Value - 0) 1; // Here you can define how ever you want values.
echo $valoare;
}
}

Thanks

praveenp

praveenp;10952675 wrote:
I guess below code may be useful for you.

$sql = "SELECT nrcont, pret FROM con_apa_rece";
$query = mysql_query($sql);
$rowCount = mysql_num_rows($query);
if($rowCount > 0){
$result = mysql_fetch_assoc($query);
$prevCol12Value = $result['col2'];
$prevPretValue = $result['col2'];
if($rowCount > 1){
while($result = mysql_fetch_assoc($query)){
$valoare = ($result['col2'] - $prevCol12Value) $prevPretValue;
$prevCol12Value = $result['col2'];
$prevPretValue = $result['col2'];
echo $valoare; // you can define how ever you want.
}
}
else
{
$valoare = ($prevCol12Value - 0) 1; // Here you can define how ever you want values.
echo $valoare;
}
}

Thanks

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