How to make a selection from the database for a certain category?

Question

PHP

The essence of the question is this: there is a very old site on pehe, two tables in MySQL
table1 (goods / services)
-----------------------
| id | name | cat_id |
-----------------------
and table2 (categories themselves and category attributes)
------------------ ---------
| id | name | desc | etc. |
---------------------------
The `cat_id` field contains entries such as:

• one
  
• 12
  
• 2
  
• ten
  
• eleven
  
• 10, 11
  
• 2, 11
  

where id categories are indicated, separated by commas. I need to select goods/services that belong to, for example, the first category.
Now, while there are no more than 20 categories, I made a quick crutch, but I urgently need a normal solution, and not this one:

$multicat = ($cat['id'] !=1 )?"(`category` REGEXP '".$cat['id']."(?=,|$)' or `category`='".$cat['id']."')":"(`category` REGEXP '".$cat['id']."(?=,)' or `category`='".$cat['id']."')";

$select = 'select `name` from `table1` where '.$multicat.' order by `id` asc');

This momentary f*ck needs to be removed urgently!
PS: all id categories separated by commas are specified in ascending order.

Answer 1

urgently need a solution

Change the database structure. There simply cannot be another solution.

Answer 2

... WHERE `category_id` LIKE '%,12,%'
upd. And generally the normal decision is a normalization of a DB. Add a link table.