DIFFERENCE (Transact-SQL)

character_expression

Is an expression of type char or varchar. character_expression can also be of type text; however, only the first 8,000 bytes are significant.

int

The integer returned is the number of characters in the SOUNDEX values that are the same. The return value ranges from 0 through 4: 0 indicates weak or no similarity, and 4 indicates strong similarity or the same values.

In the first part of the following example, the SOUNDEX values of two very similar strings are compared, and DIFFERENCE returns a value of 4. In the second part of the following example, the SOUNDEX values for two very different strings are compared, and DIFFERENCE returns a value of 0.

USE AdventureWorks2008R2;
GO
-- Returns a DIFFERENCE value of 4, the least possible difference.
SELECT SOUNDEX('Green'), SOUNDEX('Greene'), DIFFERENCE('Green','Greene');
GO
-- Returns a DIFFERENCE value of 0, the highest possible difference.
SELECT SOUNDEX('Blotchet-Halls'), SOUNDEX('Greene'), DIFFERENCE('Blotchet-Halls', 'Greene');
GO

Here is the result set.

----- ----- -----------

G650 G650 4

(1 row(s) affected)

----- ----- -----------

B432 G650 0

(1 row(s) affected)

Reference