in_array() validation not working - php

Question

So i'm trying to use in_array to call a list back from the database and then i'm checking with those results to see if the field "Title" is present in the array by doing the following.
$qGetAllTitles = "SELECT ArticleTitle FROM articles
UNION
SELECT ArticleTitle FROM temp_article";
$rGetAllTitles = mysqli_query($dbc, $qGetAllTitles);
$GetAllTitlesRow = mysqli_fetch_array($rGetAllTitles, MYSQLI_ASSOC);
if (in_array($Title, $GetAllTitlesRow['ArticleTitle'])){
$errors[0] = "The title is already taken by another article, please pick a different title";
} else {
$TTL = mysqli_escape_string($dbc, trim($Title));
$errors[0] = "Title worked";
}
I'm aware that the strings are case sensitive (and i'm looking how to negate this but that's another unrelated question)
My problem is, when i put an already used article title into the title field (which works, all other checks i use work, just not this one) it still returns "title worked", even though the check shouldn't unless the title is unique.
I've checked the SQL input in phpmyadmin (for my MySQL database) and that works getting all (3) results and the method of fetching the query is reused from elsewhere in my code, which also works, same as the in_array check so i'm really not sure why it's not working.

Answer 1

Your query returns multiple rows but you are only retrieving data for the first row. So unless the title matches the first row's title you won't find any duplicates. You need to do one of the following:
1) Loop through the result set and make an array of page titles before using in_array()
$GetAllTitlesRows = array();
while ($row = mysqli_fetch_array($rGetAllTitles, MYSQLI_ASSOC)) {
$GetAllTitlesRows[] = $row['ArticleTitle'];
}
or
2) Just search for any articles using that title right in your query which makes the code a whole lot simpler (recommended). In other words, use a WHERE clause specifically looking for that title in the ArticleTitle field. If you get any results you know it is taken.
$qGetAllTitles = "SELECT ArticleTitle FROM articles WHERE ArticleTitle = '$Title'
UNION
SELECT ArticleTitle FROM temp_article WHERE ArticleTitle = '$Title'";
$rGetAllTitles = mysqli_query($dbc, $qGetAllTitles);
if (mysqli_num_rows($rGetAllTitles) > 0){
$errors[0] = "The title is already taken by another article, please pick a different title";
}