Send the next Row if we skip the previous Row in DB – Debian

Obviously I don’t have access to your database, and I don’t know what your criteria are, so this will all be pseudocode. I am assuming you will want to delete the first row if it doesn’t match the criteria, but it would be just as possible to only skip it:

$finished = false;

while(!$finished) {
  
  // you already have the code to get the first row.  It goes here.
  // I will assume those results are in $row
  
  $finished = $row MEETS CRITERIA; // whatever these criteria are
  
  // you also have the code to delete the current row.  put that here
  // whether this row satisfies the condition or not.  The row you 
  // just selected will always be deleted
  
}

It’s as simple as that. If the row met the criteria, then $finished is TRUE and the while loop will terminate*. If the row didn’t meet the criteria, the $finished is FALSE and the while loop will run again. It will run until a row meets the criteria and $finished is TRUE.

* ! is the php NOT operator. It inverts the value. So basically what the while loop is saying is this:
while not finished { do this code }

Also, to avoid a non-terminating loop, you’ll need to make sure that your result set has something in it, or else $finished will never be set to TRUE. I’m not sure how you’re executing, so I’m not going to suggest an implementation. Just be aware that it is possible for a while to become a neverending loop and take measures to avoid it. For instance, you might:

$finished = false;
$retries = 5;

while(!$finished && $retries-->0) {
  
  //the code
  
}

This decrements $retries every loop, and once it gets to 0 the while will stop no matter what. It’s a good idea to put a failsafe in any loop that might accidentally (or unforeseenedly) become unterminated, especially during development, so you don’t hang your code.

EDITED now that I have seen some of the sample code:

$finished = false;
$retries = 5;

while(!$finished && $retries-->0) {

  $q = mysqli_query($connection, "SELECT * FROM table LIMIT 1");
  $r = mysqli_fetch_assoc($q);

  $e = $r['id'];
  $asin_queue = $r['asin'];
  $price_queue = $r['new_price'];
  
  $r = file_get_contents("https://api.keepa.com/product?asin=$asin_queue&key=$api_keepa");
  $gz = gzdecode($r);
  $t = json_decode($gz);
  $new_price = $t->products[0]->csv;  
  
  // put any other stuff you need to do here, 
  // like updating any db entries, etc

  // you also have the code to delete the current row.  put that here
  // whether this row satisfies the condition or not.  The row you 
  // just selected will always be deleted

  $finished = $new_price <= $price_queue;

}

And that’s pretty much it. It’s your existing code, just wrapped in a while block so that it loops. The only thing I’ve added is a line to check for a condition inside the while block so that the code knows when to exit.

Also, let’s look at this: $retries-->0, because that line may be a little confusing. So I said you needed some kind of failsafe to keep your code from accidentally looping forever if you make a mistake or oversight, and so I assign a variable $retries and make it equal to 5. — is php shorthand for "subtract one from this", so $retries– just subtracts one from whatever the value is currently*. >0 is just a value check, even though I wrote it so it all runs together, it’s two separate things. It could have been written like this: $retries-- > 0.

In context of the while loop, there’s a few things happening:

while( !$finished && $retries-->0 ) {}

and the whole thing has to evaluate to TRUE for the loop to keep running. && is the logical operator AND. ! is the logical operator NOT. So in plain language terms that condition would read:

"while not finished and the number of remaining retries is greater than 0, continue looping."

Hope all this helps.

* — can go before or after the variable it’s modifying. If it goes after ($retries--) then the decrement doesn’t take effect immediately. This lets you use the variable in a logical test before the decrement is applied. 5– > 4 is true. If you put the — before the variable, the decrement happens first. –5 > 4 would be false, because the subtraction will happen before the comparison.