Looping through a MySQL query in PHP - php

Question

I have some code that queries my MySQL database. My problem is, if checks only the first row of my table. I know I need to have a for loop, but what I tried out does not work. The working code that checks only the first line is
public function checkPart($aid, $uname) {
$result = mysql_query("SELECT * FROM part WHERE aid = '$aid'") or die(mysql_error());
// check for result
$no_of_rows = mysql_num_rows($result);
if ($no_of_rows > 0) {
$result = mysql_fetch_array($result);
$aiddb = $result['aid'];
$unamedb = $result['uname'];
if ($unamedb == $uname) {
// user authentication details are correct
return $result;
}
} else {
// user not found
return mysql_error();
}
}
What I tried is this:
public function checkPart($aid, $uname) {
$result = mysql_query("SELECT * FROM part WHERE aid = '$aid'") or die(mysql_error());
// check for result
$no_of_rows = mysql_num_rows($result);
for($x=1; $x<= $no_of_rows;$x++){
if ($no_of_rows > 0) {
$result = mysql_fetch_array($result);
$aiddb = $result['aid'];
$unamedb = $result['uname'];
if ($unamedb == $uname) {
// user authentication details are correct
return $result;
}
} else {
// user not found
return mysql_error();
}
}
}
Can someone please help me with correcting my code? I am a beginner so pardon me if the question is too simple.

Answer 1

The de facto way to do this is with a while loop:
$no_of_rows = mysql_num_rows($result);
if ($no_of_rows == 0) {
return mysql_error();
} else {
while ($row = mysql_fetch_assoc($result)) {
// ... use $row['aid'], $row['uname'], etc.
}
}
Your own code may work, but you were overwriting $result:
$result = mysql_fetch_array($result);
So, after one iteration of the loop, you had lost the result of the query.
Note: mysql_* functions are deprecated due to security issues, you are advised to learn mysqli_* or PDO instead.

Answer 2

public function checkPart($aid, $uname)
{
// It's think it's better to distinct the query itself
// Therefore u can re-use the code easily.
$sql = "SELECT * FROM part WHERE aid = \"$aid\"";
$result = mysql_query($sql);
// Catch errors
if (!$result)
{
die('Invalid query: ' . mysql_error());
}
// If i'm correct u're using for just to loop the result
// of fetch_array
// It's easier like in the example in the man to do
while ($row = mysql_fetch_array($result))
{
// Didn't see where this variable is used but u'll use later i suppose
$aiddb = $row['aid'];
$unamedb = $row['uname'];
if ($unamedb == $uname)
{
// user authentication details are correct
return $result;
}
else
echo 'User not found \n';
}
} // checkPart()
I'm pretty new to coding aswell but I suggest u to read the man a lot. It's really Helped me. Btw u should take a look at PDO for database query.
Source :
PHP.net fetch_array
PDO introduction