How to properly use Wildcard with CONCAT - php

Question

(Spoiler: The Title has nothing to do with what is wrong with the code.)
I'm creating a live-search system just to show the user possible event types already listed on my website. During my speculations I may have an error with Wildcard binding which I'm unable to see.
I tried using different types of "WHERE LIKE" statements, and most of them didn't work at all. Such as I tried using placeholder query (question mark) and that did not work at all. If I ran this query manually on my database I will get results which I'm expecting.
This is how my code looks, the variable $q is obtained using $_GET method.
$query = $pdo->prepare('SELECT DISTINCT EventCategory FROM Events
WHERE EventCategory LIKE CONCAT(\'%\',:q,\'%\')');
$query->bindParam(":q", $q);
$query->execute();
$row = $query->fetch(PDO::FETCH_ASSOC);
while ($row = $query->fetchObject()) {
echo "<div> $row->EventCategory </div>";
}
The expected results would be: If the $q is equal to n, Meeting and Nightlife is returned. When $q is equal to ni, then Nightlife is only returned.
The search is NOT CASE SENSITIVE, N and n is treated equally.
The SHOW CREATE TABLE Events query returned the following:
CREATE TABLE `Events` (
`ID` int(11) NOT NULL AUTO_INCREMENT,
`Name` varchar(100) NOT NULL,
`Image` varchar(600) NOT NULL,
`Date` date NOT NULL,
`Description` varchar(1200) NOT NULL,
`SpacesAvailable` int(11) NOT NULL,
`EventCategory` varchar(50) NOT NULL,
`Trending` varchar(30) DEFAULT NULL,
`TrendingID` int(255) NOT NULL,
`Sale` int(255) NOT NULL,
PRIMARY KEY (`ID`)
)DEFAULT CHARSET=latin1
Images to show the operation of the website: https://imgur.com/a/yP0hTm3
Please if you are viewing the images the view from bottom to top. Thanks

Answer 1

I suspect the default collation in your EventCategory column is case-sensitive. That's why Ni and ni don't match in Nightlife.
Try this query instead.
'SELECT DISTINCT EventCategory FROM Events WHERE EventCategory COLLATE utf8_general_ci LIKE CONCAT(\'%\',:q,\'%\')'
Or, if your column's character set is not unicode but rather iso8859-1, try this:
'SELECT DISTINCT EventCategory FROM Events WHERE EventCategory COLLATE latin1_general_ci LIKE CONCAT(\'%\',:q,\'%\')'
This explains how to look up the available character sets and collations on MySQL.
How to change collation of database, table, column? explains how to alter the default collation of a table or a column. It's generally a good idea because collations are baked into indexes.

Answer 2

The problem is not in LIKE, but in PHP and PDO. Stare at the 3 conflicting uses of $row in your code:
$row = $query->fetch(PDO::FETCH_ASSOC);
while ($row = $query->fetchObject()) {
echo "<div> $row->EventCategory </div>"; }
Then review the documentation and examples. (Sorry, I'm not going to feed you the answer; you need to study to understand it.)

Answer 3

In complement to the comprehensive answer by O.Jones, another, simpler solution would be to just perform a case-insensitive search, like :
'SELECT DISTINCT EventCategory
FROM Events
WHERE UPPER(EventCategory) LIKE CONCAT(\'%\',UPPER(:q),\'%\')'