Question

When I run the following SQL query in my Oracle database:

SELECT p.pkt_nazwa, 
       u.us_nazwa 
FROM   punkty p, 
       kategorie_uslug ku, 
       usluga u 
WHERE  ku.pkt_id = p.pktk_1_id 
       AND ku.us_id = u.usk_1_id 
ORDER  BY p.pkt_nazwa; 

I get the following output:

NAME                | SERVICE
--------------------|-------------------
Baita De Mario      | WC 
Baita De Mario      | Kuchnia
Baita De Mario      | Nocleg
Bistro-Cafe         | Bar
Bistro-Cafe         | Dyskoteka
Bistro-Cafe         | Kuchnia

How would I go about to get the following output?

NAME                | SERVICES
--------------------|-------------------
Baita De Mario      | WC, Kuchnia, Nocleg 
Bistro-Cafe         | Bar, Dyskoteka, Kuchnia

Answer 1

SELECT p.pkt_nazwa AS name, wm_concat(u.us_nazwa) AS services
FROM   punkty p
JOIN   kategorie_uslug ku ON ku.pkt_id = p.pktk_1_id
JOIN   usluga u ON u.usk_1_id = ku.us_id
GROUP  BY p.pkt_nazwa
ORDER  BY p.pkt_nazwa;

wm_concat() function is present in most versions.
More about string aggregating in Oracle.