Displaying link if no row exists in the database, otherwise display text - php

Question

I have a table called flagged_posts in my database, and it has the following columns:
id
thought_id
flagged_by_id
What I am trying to do is that if the logged in user has already flagged the post, then don't allow them to flag the post again, and I am trying to achieve this by removing the anchor link and replacing it by a message.
Here is a snippet of my code:
<?php
$query = mysqli_query($connect, "SELECT * FROM user_thoughts WHERE added_by='$user' AND shared ='yes' "."ORDER BY id DESC LIMIT {$start}, {$limit}");
while ($row = mysqli_fetch_array($query)) {
$thought_id = $row['id'];
$message_content = $row['message'];
$date_of_msg = $row['post_details'];
$thoughts_by = $row['added_by'];
$attachent = $row['attachment'];
$shared = $row['shared'];
// getting the id of the user who is logged in.
$see_if_flagged_q = mysqli_query($connect, "SELECT id FROM users WHERE username = '$username'");
$getting_deets = mysqli_fetch_assoc ($see_if_flagged_q);
$logged_in_user_id = $getting_deets ['id'];
echo "
<div class='more_options' style='float: right;'>";
$see_if_flagged_q2 = mysqli_query($connect, "SELECT * FROM flagged_posts WHERE flagged_by_id ='$logged_in_user_id' ");
while ($getting_deets2 = mysqli_fetch_assoc ($see_if_flagged_q2)){
$flagged_post_by_id = $getting_deets2 ['flagged_by_id'];
// If the user logged in has not flagged the post, i.e. there is no data in the database ..
// .. which says their user id has flagged this thought_id.. then display the link...
if ($logged_in_user_id == $flagged_post_by_id){
echo "<a href='/inc/flagged_post.php?id=$thought_id'> Flag </a>";
}
// if there is data stating this user has flagged this thought_id, then echo a message
if ($logged_in_user_id != $flagged_post_by_id) {
echo "Flagged";
}
}
echo " </div>";
}
?>
So assume I am logged in as Conor. Conor has an id of 8 (id obtained from users table). Conor flags a post with an id of 209 (thought_id obtained from user_thoughts table). So in my flagged posts table, I will see the following row:
id: 1
thought_id: 209
flagged_by_id: 8
At the moment, neither link nor the message is appearing. If I change my query, i.e. $see_if_flagged_q2 = mysqli_query($connect, "SELECT * FROM flagged_posts "); (removed the WHERE clause) then I get the message Flagged echo'd four times (because there are four rows in the flagged_posts table and they are echo's on every post, even those which have not been flagged by the logged in user.
Update:
Here is the updated code first of all:
$see_if_flagged_q2 = mysqli_query($connect, "SELECT * FROM flagged_posts WHERE flagged_by_id = '$logged_in_user_id'");
$test_num = mysqli_num_rows ($see_if_flagged_q2);
$getting_deets2 = mysqli_fetch_assoc ($see_if_flagged_q2);
$flagged_post_by_id = $getting_deets2['flagged_by_id'];
if ($flagged_post_by_id == $logged_in_user_id){
echo "<a href='/inc/flagged_post.php?id=$thought_id'> Flag </a>";
echo $test_num;
}
if ($flagged_post_by_id != $logged_in_user_id) {
echo "Flagged";
}
With the above, the link appears for all posts now, even if they are flagged. I have echo'd both $flagged_post_by_id and '$logged_in_user_id', which both echo the value of 12 (the id of Conor from users table). The values are correct and the number of rows returned by $test_num is also correct.

Answer 1

Ok, here's a reworking of your original code. I moved the data gathering part up front, so we have a setup section before we run the while loop on the thoughts. I changed a variable name here and there. Basically, we build a list of flagged entries, and then in the while loop the job is simpler. If the current row id is in the flagged_posts array, it's flagged, else present the link.
// get the id of the current user
$user_id_q = mysqli_query($connect, "SELECT id FROM users WHERE username = '$username'");
$getting_deets = mysqli_fetch_assoc($user_id_q);
$logged_in_user_id = $getting_deets['id'];
// build array of posts flagged by current user
$flagged_posts_q = mysqli_query($connect, "SELECT thought_id FROM flagged_posts WHERE flagged_by_id = '$logged_in_user_id'");
$flagged_posts = array();
while ($row = mysqli_fetch_array($flagged_posts_q)) {
$flagged_posts[] = $row['thought_id'];
}
$query = mysqli_query($connect, "SELECT * FROM user_thoughts WHERE added_by='$user' AND shared ='yes' "."ORDER BY id DESC LIMIT {$start}, {$limit}");
while ($row = mysqli_fetch_array($query)) {
//You could just use $row['foo'] down below, and skip all this
/*
$thought_id = $row['id'];
$message_content = $row['message'];
$date_of_msg = $row['post_details'];
$thoughts_by = $row['added_by'];
$attachent = $row['attachment'];
$shared = $row['shared'];
*/
echo "<div class='more_options' style='float: right;'>";
if (in_array($row['id'], $flagged_posts)){
echo "Flagged";
} else {
echo "<a href='/inc/flagged_post.php?id=".$row['id']."'> Flag </a>";
}
echo "</div>";
}