Puzzle of the Week #13: Duplicate Names

Puzzle of the Week #13

Consider the following table:

  2  FROM name_list;

---------- -----------------------------------
         1 John Smith
         2 John L. Smith
         3 Tom Blake
         4 Smith, John
         5 Tom Khan
         6 Pete Ward
         7 Peter Ward
         8 Oscar Pedro Fernando Rodriguez
         9 Rodriguez, Oscar Pedro Fernando
        10 Oscar Fernando Rodriguez Pedro
        11 KHAN, TOM S.
        12 Ward, Peter Peter

12 rows selected.

With a single SELECT statement retrieve a list of all duplicate names assuming the following:

  • Case should be ignored
  • Punctuation characters should be ignored
  • Single character initials should be ignored
  • Names are considered matching if they consist of the same set of name tokens, for ex: “John Smith” should match “SMITH, John L.” as the names consist of the same list of two tokens: John and Smith (case is ignored as well as punctuation and middle initial).

Expected Result:

   ID FULL_NAME                             GROUP_ID
---- ----------------------------------- ----------
   8 Oscar Pedro Fernando Rodriguez               1
   9 Rodriguez, Oscar Pedro Fernando              1
  10 Oscar Fernando Rodriguez Pedro               1
   1 John Smith                                   2
   2 John L. Smith                                2
   4 Smith, John                                  2
   5 Tom Khan                                     3
  11 KHAN, TOM S.                                 3

Table Setup:

CREATE TABLE name_list
    name_id   NUMBER,
    full_name VARCHAR2(100)

INSERT INTO name_list VALUES(1,'John Smith');
INSERT INTO name_list VALUES(2,'John L. Smith');
INSERT INTO name_list VALUES(3,'Tom Blake');
INSERT INTO name_list VALUES(4,'Smith, John');
INSERT INTO name_list VALUES(5,'Tom Khan');
INSERT INTO name_list VALUES(6,'Pete Ward');
INSERT INTO name_list VALUES(7,'Peter Ward');
INSERT INTO name_list VALUES(8,'Oscar Pedro Fernando Rodriguez');
INSERT INTO name_list VALUES(9,'Rodriguez, Oscar Pedro Fernando');
INSERT INTO name_list VALUES(10,'Oscar Fernando Rodriguez Pedro');
INSERT INTO name_list VALUES(11,'KHAN, TOM S.');
INSERT INTO name_list VALUES(12,'Ward, Peter Peter');


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