/* Find all tables with columns named 'course_id'   */

SELECT  table_name, column_name     
  FROM  user_tab_columns
 WHERE  column_name like  '%COURSE_ID%';              /* notice uppercase */

 
/* Find all columns having the same name across multiple tables  */

SELECT  column_name, table_name     
  FROM  user_tab_columns
ORDER BY 1,2