Aggregate data from a number of rows into a single row by Function WM_CONCAT

The Oracle PL/SQL WM_CONCAT function is used to aggregate data from a number of rows into a single row, giving a list of data associated with a specific value. In effect, it cross-tabulates a comma delimited list.

 select uc.table_name, uc.constraint_name, wm_concat(column_name) column_name
 FROM user_cons_columns ucc, user_constraints uc
   WHERE uc.constraint_name = ucc.constraint_name
     AND uc.constraint_type IN ('P', 'U')
     group by uc.table_name, uc.constraint_name
ORDER BY 1, 2;