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.

 

here is what i wrote:

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;
}

 

 

can someone help?

 

thank you,

[kenrbnsn]

The mysql_query function does not return a value, it returns a pointer to the results. You need to use a fetch function such as mysql_fetch_assoc to get the actual values.

 

Ken

[sebatm]

Thank's Ken.

 

But is still get an Parse Error for the following row.

($valoare=($i['nrcont']-[$i-1]['nrcont'])*$pret['pret']);

 

I haven't found anything similar on the internet to check the syntax.

 

Sebastian

[Mchl]

You still get it, because you're still using your $pret variable wrong.

 

See examples here -> mysql_query