Sql search from 2 or 3 table - php

Question

I have a search form where I can search for my webshop products.
1 product can be in multiple categoris, not just in one. I store this in the termek_katgoria_kapcsolo table. At insert, it creates as many lines, as the product belong to many categoria.
Example: The ID 12 product belong to ID 1, ID 2, ID 3 categoria.
The search sql only look at categoria, when one categoria is selected. Most often, I just search for the products name, I don't sort it to categoris.
How can I write the sql, that if I select a categoria also? I show you the tables on a pic.
if($termek_kategoria == 0 ) // Sort to categoria or not only search for product name, id...
{
$sql = "
SELECT termek_id, termek_nev, termek_cikkszam, termek_status FROM termek
WHERE $kereses_helye LIKE '%$kw%' ORDER BY $kereses_rendezes $kereses_sorrend
";
}
else
{
// Sorting for categoria also
$sql = "
SELECT termek_id, termek_nev, termek_cikkszam, termek_status FROM termek
WHERE $kereses_helye LIKE '%$kw%' AND termek_kategoria =
'$termek_kategoria' ORDER BY $kereses_rendezes $kereses_sorrend
";
}
Update:
$sql = "
SELECT termek.termek_id, termek.termek_nev, termek.termek_cikkszam, termek.termek_status
termek_kategoria_kapcsolo.*, termek_kategoria.kat_id
FROM termek
LEFT JOIN termek_katgoria_kapcsolo ON termek_kategoria
WHERE termek_kategoria_kapcsolo.kat_kapcs_kategoria_id = termek_kategoria.kat_id
AND termek.termek_id IN (SELECT kat_kapcs_termek_id FROM
termek_kategoria_kapcsolo WHERE kat_kapcs_kategoria_id = '$termek_kategoria')
";
This result:
Whats going wrong here?
What I want is when I select a categoria, the program give me the products, that are in the selected categoria.

Answer 1

I solved the problem:
$sql =
"
SELECT
t.termek_id,
t.termek_nev,
t.termek_cikkszam,
t.termek_status,
kapcs.kat_kapcs_kategoria_id,
kapcs.kat_kapcs_termek_id
FROM termek t
LEFT JOIN termek_katgoria_kapcsolo kapcs ON kapcs.kat_kapcs_kategoria_id = '$termek_kategoria'
WHERE t.termek_id = kapcs.kat_kapcs_termek_id AND t.$kereses_helye LIKE '%$kw%' ORDER BY t.$kereses_rendezes $kereses_sorrend
";