EDIT_DISTANCE

Calculates and returns the Levenshtein distance between two strings. The return value indicates the minimum number of single-character edits—insertions, deletions, or substitutions—that are required to change one string into the other.

Behavior type

Syntax

EDIT_DISTANCE ( string-expression1, string-expression2 )

Arguments

string-expression1, string-expression2

The two VARCHAR expressions to compare.

Examples

The Levenshtein distance between kitten and knitting is 3:

=> SELECT EDIT_DISTANCE ('kitten', 'knitting');
 EDIT_DISTANCE
---------------
             3
(1 row)

EDIT_DISTANCE calculates that no fewer than three changes are required to transform kitten to knitting:

1. kitten → knitten (insert n after k)

2. knitten → knittin (substitute i for e)

3. knittin → knitting (append g)