Skip to content

Instantly share code, notes, and snippets.

@radityopw radityopw/levenshtein
Last active Aug 29, 2015

Embed
What would you like to do?
levenshtein distance in sqlserver
CREATE FUNCTION [dbo].[LEVENSHTEIN]( @s NVARCHAR(MAX), @t NVARCHAR(MAX) )
/*
Levenshtein Distance Algorithm: TSQL Implementation
by Joseph Gama
http://www.merriampark.com/ldtsql.htm
Returns the Levenshtein Distance between strings s1 and s2.
Original developer: Michael Gilleland http://www.merriampark.com/ld.htm
Translated to TSQL by Joseph Gama
Fixed by Herbert Oppolzer / devio
as described in https://devio.wordpress.com/2010/09/07/calculating-levenshtein-distance-in-tsql
*/
RETURNS INT AS
BEGIN
DECLARE @d NVARCHAR(MAX), @LD INT, @m INT, @n INT, @i INT, @j INT,
@s_i NCHAR(1), @t_j NCHAR(1),@cost INT
--Step 1
SET @n = LEN(@s)
SET @m = LEN(@t)
SET @d = REPLICATE(NCHAR(0),(@n+1)*(@m+1))
IF @n = 0
BEGIN
SET @LD = @m
GOTO done
END
IF @m = 0
BEGIN
SET @LD = @n
GOTO done
END
--Step 2
SET @i = 0
WHILE @i <= @n BEGIN
SET @d = STUFF(@d,@i+1,1,NCHAR(@i)) --d(i, 0) = i
SET @i = @i+1
END
SET @i = 0
WHILE @i <= @m BEGIN
SET @d = STUFF(@d,@i*(@n+1)+1,1,NCHAR(@i)) --d(0, j) = j
SET @i = @i+1
END
--Step 3
SET @i = 1
WHILE @i <= @n BEGIN
SET @s_i = SUBSTRING(@s,@i,1)
--Step 4
SET @j = 1
WHILE @j <= @m BEGIN
SET @t_j = SUBSTRING(@t,@j,1)
--Step 5
IF @s_i = @t_j
SET @cost = 0
ELSE
SET @cost = 1
--Step 6
SET @d = STUFF(@d,@j*(@n+1)+@i+1,1,
NCHAR(dbo.MIN3(
UNICODE(SUBSTRING(@d,@j*(@n+1)+@i-1+1,1))+1,
UNICODE(SUBSTRING(@d,(@j-1)*(@n+1)+@i+1,1))+1,
UNICODE(SUBSTRING(@d,(@j-1)*(@n+1)+@i-1+1,1))+@cost)
))
SET @j = @j+1
END
SET @i = @i+1
END
--Step 7
SET @LD = UNICODE(SUBSTRING(@d,@n*(@m+1)+@m+1,1))
done:
RETURN @LD
END
create function [dbo].[min3](@a int, @b int, @c int)
returns int as
begin
declare @min int
set @min = @a
if @b < @min set @min = @b
if @c < @min set @min = @c
return @min
end
select a.nama,b.nama,dbo.LEVENSHTEIN(a.nama,b.nama)
from tabel1 a inner join tabel2 b on a.kde....b.kde......
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
You can’t perform that action at this time.