I cant write the correct SQL query correcty - mysql

Question

I have 2 table in the database and ı am trying to filter some users according to some criterias.
criterias table
+---------+----------------------+--------------------+----------------------+
| user_id | searching_friendship | searching_practice | conversation_subject |
+---------+----------------------+--------------------+----------------------+
| 31 | | | science |
| 26 | on | on | love |
| 32 | on | off | science |
| 34 | | | |
+---------+----------------------+--------------------+----------------------+
user table
+---------+------------+-----------------------------+---------------+-------------+---------------+--------------+------------------+
| user_id | user_name | user_email | user_password | user_gender | user_language | language_lvl | last_login |
+---------+------------+-----------------------------+---------------+-------------+---------------+--------------+------------------+
| 26 | Furkan | furkanakgun#windowslive.com | 123 | | Türkiye | basic | 16.06.2019 11:57 |
| 31 | sfsdf | asdfasdf#hotmail.com | 123 | Male | Afrikaans | basic | 09.06.2019 20:01 |
| 32 | denemeuser | xxx#hotmail.com | 123 | Male | Amharic | intermediate | 16.06.2019 11:57 |
| 33 | Smith | ssdf | 123 | male | ing | upper | NULL |
| 34 | luser | llll#hotmai.com | 123456 | Male | Afrikaans | basic | 16.06.2019 10:32 |
+---------+------------+-----------------------------+---------------+-------------+---------------+--------------+------------------+
I am trying to match users who have same criterias.What i do is
$userId=$_SESSION['userId'];
$sql="SELECT* FROM criterias WHERE user_id='$userId'";
$query=mysqli_query($conn,$sql);
while($result=mysqli_fetch_assoc($query)){
$friendshipCheck=$result['searching_friendship'];
$pracCheck=$result['searching_practice'];
$conversationSub=$result['conversation_subject'];
}
so I am getting current criterias informations and ı am trying to match with other users like this
SELECT* FROM users,criterias WHERE (users.user_id=criterias.user_id AND users.user_id!='$userId') AND criterias.searching_friendship='$friendshipCheck' OR criterias.searching_practice='$pracCheck'
But it doesnt work. Do you have any idea how to fix this dear friends ?

Answer 1

If you want to get only the users with the same criteria as yours this query should work
SELECT *
FROM users AS u
INNER JOIN criterias AS c ON u.user_id = c.user_id
WHERE u.user_id != '$userId'
AND c.searching_friendship = '$friendshipCheck'
AND c.searching_practice = '$pracCheck'
AND c.conversation_subject = '$conversation_subject'

Answer 2

Providing the expected results vs what you are getting would help proving the best solution.
Here, I am trying to write the query based on the understanding of what you have tried to write in your code:
;WITH CTE AS
(
SELECT C.*
FROM Criterias C
WHERE C.user_id = <user_id_input>
)
SELECT *
FROM User U
INNER JOIN Criterias C
ON U.user_id = C.user_id
WHERE EXISTS (
SELECT 1
FROM CTE
WHERE CTE.searching_friendship = C.searching_friendship
OR CTE.searching_practice = C.searching_practice
)
AND U.user_id != <input_user_id> ;