Concate values of a certain column in a different column depending on id in SQL

id	col1
1	John
1	Mary
2	Patricia
2	Charlie
3	Jane
3	Karen
3	MJ
3	Roland

The output should look like this

id	values
1	John,Mary
2	Patricia, Charlie
3	Jane, Karen, MJ,Roland

Answer

In MySQL, MariaDB and SQLite, you can use the GROUP_CONCAT aggregation function:

SELECT id,
       GROUP_CONCAT(col1) AS values_
FROM tab
GROUP BY id

In PostgreSQL and SQL Server, you can use the STRING_AGG aggregation function:

SELECT id,
       STRING_AGG(col1, ',') AS values_
FROM tab
GROUP BY id

In Oracle and DB2, you can use the LISTAGG aggregation function:

SELECT id,
       LISTAGG(col1, ',') WITHIN GROUP(ORDER BY col1) AS values_
FROM tab
GROUP BY id