Alan.B
I came up with this:
-- strings to compare
DECLARE@s1 varchar(8000)='diner',
@s2 varchar(8000)='dinerr';
DECLARE @Ld int=ABS(LEN(@s1)-LEN(@s2));
IF ((@s1=@s2) OR ((ISNULL(LEN(@s1)*LEN(@s2),0)=0))) BEGIN GOTO LD END;
DECLARE@minlen int=CASE WHEN LEN(@s1)>LEN(@s2) THEN LEN(@s2) ELSE LEN(@s1) END;
;WITH
nums(n) AS (SELECT ROW_NUMBER() OVER (ORDER BY (SELECT 0)) FROM [master].dbo.spt_values Tally),
matrix AS (SELECT SUBSTRING(@s1,n,1) s1, SUBSTRING(@s2,n,1) s2 FROM nums WHERE n<=@minlen)
SELECT @Ld+=COUNT(*) FROM matrix WHERE s1<>s2;
LD:
SELECT @Ld AS LD;
Alan, I had never heard of this either. If the Wiki description Dwain posted is to be trusted, I think you might want to re-visit this. For example, for the two strings you provided, 'diner' and 'dinerr', the output is 1. This makes sense, because all you have to do is delete the second 'r' in string 2 (or the first 'r' for that matter), and you end up with the same two strings. Next, let's say I change the 'd' in string 1 to 'a'. The code returns 2, which I think is correct, since all I have to do is substitute 'a' in string 1 to 'd', then delete one of the 'r' in string 2, and I have two of the same string. Now, consider this: let's say I insert the 'a' in string 1, but leave the rest intact, leaving me with 'adiner' for string 1, and I leave string 2 as 'dinerr'. The code returns a value of 5. This does not make sense, again, if Wiki is to be trusted, as it states the allowable actions are single character insertions, deletions, and substitutions. So, in order to make 'adiner' = 'dinerr', I only need two actions: delete the 'a' in 'adiner', and delete one of the 'r' in 'dinerr'. Does that make sense, or am I missing something? (the latter is entirely possible.) (maybe even likely).
Greg
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