回显PHP数组不返回结果

Question

So, guys, my problem is that i'm creating an array from a mysql column, but, when i echo the array items, it returns me nothing, i'm about this for a while and i'm not seeing a possible error, hope can get some help. Here' s my code: (I know about the mysql to mysqli, but i'm just beginning and trying the logical stuff. :))

$duracao = mysql_query(
    "SELECT SUM(fim_periodo-inicio_periodo)/0.01666667 AS mysum
 FROM afunda_eleva_$a"
); //THIS $duracao IS INSIDE A FOR LOOP THAT EXECUTES THE QUERY IF A CONDITION IS SATISFIED (DEPENDING ON $a and $prevNum), it is working fine!

while ($row2 = mysql_fetch_assoc($duracao))
{
    $duracao_afunda_eleva[] = $row2['mysum'];
}

so, to test some possible problems, i've put:

$i2 = sizeof($duracao_afunda_eleva);    
echo $i2;
echo <br>;

which returns me the right size of the array, the problem comes here, i think:

for($i1 = 0 ; $i1 < sizeof($duracao_afunda_eleva); $i1++)    
{
    echo $duracao_afunda_eleva[$i1] or die("couldn't echo"
    . mysql_error());        
    echo "<br>";    
}

and this returns me no value. I really would appreciate any suggestion. Thanks in advance!

Answer 1

Try print_r instead of echo - echo outputs (string)$variable, which in case of an array is just "array". Also, echo is a language construct and not a function, so your or die(...) is problematic, as language constructs don't have return values.

Generally it's better to not use or die(...) constructs, and handle problems correctly (using a defined return value, so cleanup code can run, for example). Also, not being able to output anything with echo would mean that your php/whatever installation is seriously gone bad, at which point you probably won't even reach that line in your code, and even then it won't have anything to do with mysql.