MySQL group result

Question

I need to group MySQL result, from property table and category table but I can't understand how can I do it ?

I have 6 category column in property table

SELECT p.*, c.*, p.id id
                  FROM property p
                  JOIN clients c
                    ON p.user_id = c.id
                  LEFT JOIN category ct1
                    ON ct1.id = p.cat1
                  LEFT JOIN category ct2
                    ON ct2.id = p.cat2
                  LEFT JOIN category ct3
                    ON ct3.id = p.cat3
                  LEFT JOIN category ct4
                    ON ct4.id = p.cat4
                  LEFT JOIN category ct5
                    ON ct5.id = p.cat5
                  LEFT JOIN category ct6
                    ON ct6.id = p.cat6
                 WHERE public = '1'
                   AND (p.cat1 = '$cat'
                    OR p.cat2 = '$cat'
                    OR p.cat3 = '$cat'
                    OR p.cat4 = '$cat'
                    OR p.cat5 = '$cat'
                    OR p.cat6 = '$cat')
                 GROUP BY ct1.id, ct2.id, ct3.id, ct4.id, ct5.id, ct6.id
                 ORDER BY p.id DESC

I need 5 result where cat ID is "41"

Thank you

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EDITED:

I think this method is not for me, because I have multi category column

can anyone help me?

$SQL = "SELECT p.*, c.*, p.id id
          FROM property p
          JOIN clients c
            ON p.user_id = c.id
         WHERE public = '1'
           AND p.cat1 IN ($cat)
            OR p.cat2 IN ($cat)
            OR p.cat3 IN ($cat)
            OR p.cat4 IN ($cat)
            OR p.cat5 IN ($cat)
            OR p.cat6 IN ($cat)
         ORDER BY p.id DESC";

I get only one result, but I need three result, two times ID 99 and one times 93

Thank you