# name: test/sql/function/string/test_levenshtein.test
# description: Test levenshtein function
# group: [string]

statement ok
PRAGMA enable_verification


# normal queries
query I
SELECT levenshtein('hallo', 'hallo')
----
0

query I
SELECT levenshtein('hallo', 'hello')
----
1

query I
SELECT levenshtein('hello', 'hallo')
----
1

query I
SELECT levenshtein('lawn', 'flaw')
----
2

query I
SELECT levenshtein('flaw', 'lawn')
----
2

query I
SELECT levenshtein('kitten', 'sitting')
----
3

query I
SELECT levenshtein('sitting', 'kitten')
----
3

query I
SELECT levenshtein('hallo', 'hoi')
----
4

query I
SELECT levenshtein('hoi', 'hallo')
----
4

query I
SELECT levenshtein(NULL, 'hi')
----
NULL

query I
SELECT levenshtein('hi', NULL)
----
NULL

query I
SELECT levenshtein(NULL, NULL)
----
NULL

query I
SELECT levenshtein('', NULL)
----
NULL

query I
SELECT levenshtein(NULL, '')
----
NULL

query I
SELECT levenshtein('', 'hi')
----
2

query I
SELECT levenshtein('hi', '')
----
2

query I
SELECT levenshtein('', '')
----
0


statement ok
CREATE TABLE strings(s VARCHAR)

statement ok
INSERT INTO strings VALUES ('hello'), ('hallo'), ('aloha'), ('fello'), ('fellow'), ('ducks')

query I
SELECT levenshtein(s, 'hallo') FROM strings ORDER BY s
----
4
5
2
3
0
1

query I
SELECT levenshtein('hallo', s) FROM strings ORDER BY s
----
4
5
2
3
0
1

query I
SELECT levenshtein(NULL, s) FROM strings
----
NULL
NULL
NULL
NULL
NULL
NULL

query I
SELECT levenshtein(NULL, s) FROM strings
----
NULL
NULL
NULL
NULL
NULL
NULL

query I
SELECT levenshtein('', s) FROM strings ORDER BY s
----
5
5
5
6
5
5

query I
SELECT levenshtein(s, '') FROM strings ORDER BY s
----
5
5
5
6
5
5


statement ok
DROP TABLE strings

statement ok
CREATE TABLE strings(s VARCHAR)

statement ok
INSERT INTO strings VALUES (NULL)

query I
SELECT levenshtein(s, NULL) from strings
----
NULL

query I
SELECT levenshtein(NULL, s) from strings
----
NULL

query I
SELECT levenshtein('hi', s) from strings
----
NULL

query I
SELECT levenshtein(s, 'hi') from strings
----
NULL

query I
SELECT levenshtein('', s)  FROM strings
----
NULL

query I
SELECT levenshtein(s, '')  FROM strings
----
NULL


statement ok
DROP TABLE strings

statement ok
CREATE TABLE strings(s VARCHAR)

statement ok
INSERT INTO strings VALUES ('')

query I
SELECT levenshtein(NULL, s)  FROM strings
----
NULL

query I
SELECT levenshtein(s, NULL)  FROM strings
----
NULL

query I
SELECT levenshtein(s, '')  FROM strings
----
0

query I
SELECT levenshtein('', s)  FROM strings
----
0

query I
SELECT levenshtein(s, 'hi')  FROM strings
----
2

query I
SELECT levenshtein('hi', s)  FROM strings
----
2


# editdist3
query I
SELECT editdist3('hallo', 'hello')
----
1

query I
SELECT editdist3(s, 'hello') FROM strings
----
5

# Comparing fields from two columns row wise

statement ok
DROP TABLE strings

statement ok
CREATE TABLE strings(s VARCHAR, t VARCHAR)

statement ok
INSERT INTO strings VALUES 	('hello', 'hello'), ('hello', 'hallo'), ('flaw', 'lawn'),
							('sitting', 'kitten'), ('hallo', 'aloha'), ('hello', 'aloha'),
							(NULL, NULL), ('', ''),
							(NULL, 'bora'), ('bora', NULL),
							('hi', ''), ('', 'hi'),
							(NULL, ''), ('', NULL)


query I
SELECT levenshtein(s, t) ld FROM strings
----
0
1
2
3
4
5
NULL
0
NULL
NULL
2
2
NULL
NULL