DLE_DST ​

Return the difference between two character strings in terms of the number of changes required to convert the first string into the second. The comparison of the strings is case-sensitive. This function uses the Damerau-Levenshtein edit distance algorithm to compute the "distance" between the strings. With this algorithm, a character transposition change such as 'ab' to 'ba' counts as one change, not two.

See also LE_DST.

Usage Notes ​

This function returns an integer.

Two configuration parameters affect the performance and memory usage of this function. See max_levenshtein_distance and max_levenshtein_string_size for more information.

Examples ​

The following example requires two changes, one for the case of the letter C, and one for the transposition of kc:

yellowbrick=# select dle_dst('Chekcing','checking') from sys.const;
 le_dst 
--------
     2
(1 row)

Calculate the distance between London team names and their nicknames in the team table:

premdb=# select name, nickname, dle_dst(name,nickname) dledst from team where city='London' and name is not null order by 3 desc;
       name         |  nickname  | dledst 
---------------------+------------+--------
 Queens Park Rangers | Hoops      |     18
 Charlton Athletic   | Addicks    |     16
 Tottenham Hotspur   | Spurs      |     15
 West Ham United     | Hammers    |     12
 Crystal Palace      | Eagles     |     12
 Wimbledon           | Dons       |      8
 Chelsea             | Pensioners |      8
 Fulham              | Cottagers  |      8
 Arsenal             | Gunners    |      6
(9 rows)

See also the examples for LE_DST.