Loop through two while arrays - php

Question

I am making this post system with like button and count for a social networking site.
My end goal is to loop through these two sets of results together. So that the like counts goes with the individual posts as they loop. The posts and likes are in desc order. Everything matches except I can't get these while fetch results to loop together.
Post loop
<table class="postborder">
<?php
$query1 = "SELECT * FROM tbl_images ORDER BY id DESC";
$result = mysqli_query($connect, $query1);
while($row = mysqli_fetch_array($result)) {
?>
<div id="newpost">
<tr>
<td id="userpost"><?php echo $row['username']; ?> </td>
</tr>
<tr>
<td>
<hr id="hrline">
<img id="newimgpost" src="data:image/jpeg;base64,<?php echo base64_encode($row['name']); ?>" height="500" width="500" class="img-thumnail" />
</td>
<tr>
<td id="textpost">
<?php echo $row['textpost']; ?>
</td>
</tr>
<tr>
<td id="likebutton">
<?php } ?>
</div>
</table>
Like count loop
<?php
//index.php
//session_start();
//SESSION['userid'] = (int)3;
$connect = mysqli_connect("localhost", "root", "", "snazzer");
$query2 = "
SELECT tbl_images.id, tbl_images.textpost,
COUNT(likes.id) as likes,
GROUP_CONCAT(users.name separator '|') as liked
FROM
tbl_images
LEFT JOIN likes
ON likes.postid = tbl_images.id
LEFT JOIN users
ON likes.userid = users.userid
GROUP BY tbl_images.id
ORDER BY id DESC
";
$result2 = mysqli_query($connect, $query2);
if (!$result2) {
printf("Error: %s\n", mysqli_error($connect));
exit();
}
while($row = mysqli_fetch_array($result2))
{
echo '<h3>'.$row["textpost"].'</h3>';
echo '
LIKE';
echo '<p>'.$row["likes"].' People like this</p>';
if(count($row["liked"]))
{
$liked = explode("|", $row["liked"]);
echo '<ul>';
foreach($liked as $like)
{
echo '<li>'.$like.'</li>';
}
echo '</ul>';
}
}
if(isset($_GET["type"], $_GET["id"]))
{
$type = $_GET["type"];
$id = (int)$_GET["id"];
if($type == "postid")
{
$query = "
INSERT INTO likes (userid, postid)
SELECT {$_SESSION['userid']}, {$id} FROM tbl_images
WHERE EXISTS(
SELECT id FROM tbl_images WHERE id = {$id}) AND
NOT EXISTS(
SELECT id FROM likes WHERE userid = {$_SESSION['userid']} AND postid = {$id})
LIMIT 1
";
mysqli_query($connect, $query);
header("location:profile.php");
}
}
?>

Answer 1

I believe you could run two queries together. It's fairly simple; just separate each query with semicolon:
$query = "SELECT * FROM tbl_images ORDER BY id DESC;
SELECT tbl_images.id, tbl_images.textpost, COUNT(likes.id) as likes, GROUP_CONCAT(users.name separator '|') as liked FROM tbl_images LEFT JOIN likes ON likes.postid = tbl_images.id LEFT JOIN users ON likes.userid = users.userid GROUP BY tbl_images.id ORDER BY id DESC";
Or separate the variable by incrementing values, you can read their documentation which explains it here.
$query = "SELECT * FROM tbl_images ORDER BY id DESC";
$query .= "SELECT tbl_images.id, tbl_images.textpost, COUNT(likes.id) as likes, GROUP_CONCAT(users.name separator '|') as liked FROM tbl_images LEFT JOIN likes ON likes.postid = tbl_images.id LEFT JOIN users ON likes.userid = users.userid GROUP BY tbl_images.id ORDER BY id DESC";
Then run your code as you normally would except you change mysqli_query to mysqli_multi_query:
$result = mysqli_multi_query( $connect, $query );
while($row = mysqli_fetch_array( $result )) {
//... code your table here ...//
}
You can also the Object-Oriented method which works pretty well:
$result = $connect->multi_query( $query );
But of course both methods should work fine. Do keep in mind, you may be vulnerable to SQL Injections with mysqli_multi_query. This is PHP's official warning:
Security considerations
The API functions mysqli_query() and mysqli_real_query() do not set a connection flag necessary for activating multi queries in the server. An extra API call is used for multiple statements to reduce the likeliness of accidental SQL injection attacks. An attacker may try to add statements such as ; DROP DATABASE mysql or ; SELECT SLEEP(999). If the attacker succeeds in adding SQL to the statement string but mysqli_multi_query is not used, the server will not execute the second, injected and malicious SQL statement.
Considerations
You could always save both results from your while loop in an array and run them in a foreach loop or have them output individually as $array['key']. Which would be a simple workaround to your queries:
<?php
// first query
$query1 = "SELECT * FROM tbl_images ORDER BY id DESC";
$result = mysqli_query($connect, $query1);
while($row = mysqli_fetch_array($result)) {
$array1[] = $row;
}
// second query
$query2 = "
SELECT tbl_images.id, tbl_images.textpost,
COUNT(likes.id) as likes,
GROUP_CONCAT(users.name separator '|') as liked
FROM
tbl_images
LEFT JOIN likes
ON likes.postid = tbl_images.id
LEFT JOIN users
ON likes.userid = users.userid
GROUP BY tbl_images.id
ORDER BY id DESC
";
$result2 = mysqli_query($connect, $query2);
while($row = mysqli_fetch_array($result2)) {
$array2[] = $row;
}
Once you have those records setup you can now use $array1 and $array2 to setup your table.
To get their keys and setup you can use print_r or var_dump and you will be able to see key => value pairs:
print_r( $array1 );
echo '<br />';
print_r( $array2 );