Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE tags ( index number, id number, tag text )
TABLE: CREATE TABLE torrents ( groupname text, totalsnatched number, artist text, groupyear number, releasetype text, groupid number, id number )

### Question ###
What are the artist/groups that released only one CD?

### Accurate SQL ###

SELECT artist FROM torrents GROUP BY artist HAVING COUNT(*) = 1