Mysql_query更新

Question

I could swear that I had this working last week, but now I get errors.

In PHP I have a large CSV file that I run through a foreach loop and in this loop I have a created a variable that adds an UPDATE line to itself, like this:

foreach ($csv->data as $value){
   $updater .= "UPDATE tblProduktData SET xtra = 2 WHERE id = '$value[1]';";
}
mysql_query("$updater") or die(mysql_error());

The CSV file contains over 3000 lines so having the mysql_query() inside the loop obviously makes the process slow and is not recommendable.

Can anyone tell me if I'm missing something or just doing it wrong?

Answer 1

We will temporarily ignore the fact that you are using a PHP extension mysql_ that has been deprecated ( Scheduled for removal from the language) for a number of years now.

For some reason you are adding to the sql query each time through the loop by using the .= syntax. I assume you thought you could run more than one query at a time using the mysql_ extension, but you cannot.

So try this :-

foreach ($csv->data as $value){
   $updater = "UPDATE tblProduktData SET xtra = 2 WHERE id = '$value[1]'";
   mysql_query($updater) or die(mysql_error());
}

This is in fact a perfect candidate for using mysqli_ or PDO prepared statements.

The mysqli_ extension manual

The PDO manual

Answer 2

Try this:

$id = "0"; // initialze the ids to update with a non-existing value
// fetch all the ids into a variable
foreach ($csv->data as $value){
  $id .= "," . $value[1] 
}

$updater .= "UPDATE tblProduktData SET xtra = 2 WHERE id in (".$id.") ;";
mysql_query("$updater") or die(mysql_error());