Appending many mysql_fetch_array results

Question

while($row=mysqli_fetch_array($result)) { echo $row['sth']; .....}
1. $row = mysqli_fetch_array($result); while($row) { echo $row['sth']; .....}

When I change first while loop to second, I get an infinite loop. Is there a way I can do fetch_array before the while loop and not get an infinite loop?

The reason I'm trying this is...:

So I have select multiple name=options[] delivered through $_POST.
Then I am using foreach($_POST['options'] as $option) to SELECT indexes whose field value matches $option. After that, if I do a while loop as in 1. from the above, I only get the elements of the last options[].
So I want to append the results of mysqli_fetch_array to an array $row and then do a while loop as in 2. But I get an infinite loop like said.

I know my explanation is a bit confusing.... If it isn't clear up to this point, read more below. I am explaining in more details with more codes provided.

========================================================================
if(isset($_POST['options'])) {
    foreach($_POST['options'] as $option) {
            $query = "SELECT * FROM users WHERE stdYr = '$option'";
            $result = mysqli_query($db_conx, $query) or die("Error in ".$query."<br>".mysqli_error($db_conx));
        }
    }
}
while($row=mysqli_fetch_array($result)) {}

With this code, when an array options[option1, option2, option3] is passed, for example, the result only outputs the elements of options[option3]. Query output of option1 and option2 is overwritten in foreach loop.
So I came up with an attempt to declare fetch_array inside foreach loop and append in to $result like this:

========================================================================
if(isset($_POST['options'])) {
    foreach($_POST['options'] as $option) {
            $query = "SELECT * FROM users WHERE stdYr = '$option'";
            $result = mysqli_query($db_conx, $query) or die("Error in ".$query."<br>".mysqli_error($db_conx));
            $row.=mysqli_fetch_array($result)
        }
    }
}
while($row) {}

BUT this results in infinite loop.....

Can someone help? Let me know if this doesnt make sense... Thanks ! :D

Something tells me that your design got something wrong. Usually I really despise queries inside a loop. What I usually do is populate what I need before (like getting a list of IDs) and then execute another query using IN (youridshere). Last but not least, if data is not extremely huge I prefer to collect it in arrays and then used in other queries and so on. PS: SANITIZE your $_POSTs too! :) — Oliver M Grech
– Oliver M Grech, Commented Dec 23, 2014 at 14:28

kos · Accepted Answer · 2014-12-23 15:14:02Z

1

Use do-while instead of while. That way you can move the first mysql_fetch_array() call out of the loop:

<?php
    // code
    $row=mysql_fetch_array($result);
    if($row) {
        do
            echo $row["sth"];
        while($row=mysql_fetch_array($result));
    }
    //code
?>

edited Dec 23, 2014 at 15:14

answered Dec 22, 2014 at 15:21

kos

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vaso123 · Accepted Answer · 2014-12-23 14:08:23Z

0

Your problem is, you are always overwriting your variable inside the loop. Use it as an array.

EDIT: My fault, I've added the result as an array, not the row.

Change this:

foreach ($_POST['options'] as $option) {
    $query = "SELECT * FROM users WHERE stdYr = '$option'";
    $result = mysqli_query($db_conx, $query) or die("Error in " . $query . "<br>" . mysqli_error($db_conx));
    $row[] = mysqli_fetch_array($result);
}

(added the [] after the $row, so now it's $row[]. Outside of the loop, says var_dump($row);

After this, you can set up a new foreach loop. Do not add the while loop to it.

edited Dec 23, 2014 at 14:08

answered Dec 22, 2014 at 14:55

vaso123

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3 Comments

Megool Over a year ago

This exacrly is my problem. Ill give iy a try and get back to you. Thanks!

Megool Over a year ago

After changing to $result[], I get mysqli_fetch_array() expects parameter 1 to be mysqli_resulterror message on while($row=mysqli_fetch_array($result)).

vaso123 Over a year ago

Check my edited post, sorry, that was my fault. I've added the result as an array, not the row. And rename the $row to $rows everywhere :)

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