How to write a query that does something similar to MySQL's GROUP_CONCAT in Oracle?

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         


        

Answer 1

Here's an article explaining some approaches to what you're trying to do in Oracle:

http://www.oracle-base.com/articles/misc/StringAggregationTechniques.php

Note that if you're running 11g Release 2 then LISTAGG is the way to go.

Answer 2

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.

Answer 3

Since Oracle 11.2 this has become easier using listagg()

SELECT p.pkt_nazwa AS name, 
       listagg(u.us_nazwa) WITHIN GROUP (ORDER BY 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;