Using mysql_fetch_assoc and updating each record - php

Question

Some of my rows have a "," comma as the initial character in the field. So I need to loop through, check if each row has the initial commma, remove it if it does, and update the row.
I am running the following code, which seems to go on an endless loop when the update is called.
When I am just echoing out the result at the end, everything looks fine in the browser. But on execution of the update line below the echo, it seems as if a single datum from the column "Tags" is being populated for every record, instead of just the rows that have the initial commma that I am removing.
Would love help :)
$query = mysql_query("SELECT Tags FROM products")
or die (mysql_error());
while ($row = mysql_fetch_assoc($query))
{
$str = $row['Tags'];
$initial = substr($str,0,1);
if ($initial = ",") {
$str = (ltrim($str, ','));
}
echo "result: " .$str . "<br/>";
$result = "UPDATE products SET Tags = '" .$str ."'";
mysql_query($result);
}
Thank you.

Answer 1

You should pass the particular row id to the one you're making changes to, by using a WHERE clause:
$query = mysql_query("SELECT Tags FROM products")
or die (mysql_error());
while ($row = mysql_fetch_assoc($query)) {
$str = $row['Tags'];
$initial = substr($str,0,1);
if ($initial == ",") {
// == not =
$str = (ltrim($str, ','));
}
$id = $row['id'];
echo "result: " .$str . "<br/>";
$result = "UPDATE products SET Tags = '$str' WHERE id = $id";
mysql_query($result);
}
By the way, if possible kindly change to the better extension which is mysqli or PDO instead.

Answer 2

You're if() statement has an error in it.
You're using one equal:
if($initial = ",") {
}
Instead of two for actual comparison:
if($initial == ",") {
}

Answer 3

Here is the complete code. Thank you everyone.
$query = mysql_query("SELECT ProductID, Tags FROM products")
or die (mysql_error());
while ($row = mysql_fetch_assoc($query)) {
$str = $row['Tags'];
$initial = substr($str,0,1);
if ($initial == ",") {
$str = (ltrim($str, ','));
$id = $row['ProductID'];
//echo $id . " ";
//echo $str . "<br/>";
$result = "UPDATE products SET Tags = '$str' WHERE ProductID = $id";
echo $result ."<br>";
mysql_query($result);
}
}
So grateful for the help. I will update to mysqlli also.