This function returns an integer value measuring the difference between the SOUNDEX() values of two different character expressions.
Transact-SQL Syntax Conventions
DIFFERENCE ( character_expression , character_expression )
character_expression
An alphanumeric expression of character data. character_expression can be a constant, variable, or column.
int
DIFFERENCE
compares two different SOUNDEX
values, and returns an integer value. This value measures the degree that the SOUNDEX
values match, on a scale of 0 to 4. A value of 0 indicates weak or no similarity between the SOUNDEX values; 4 indicates strongly similar, or even identically matching, SOUNDEX values.
DIFFERENCE
and SOUNDEX
have collation sensitivity.
The first part of this example compares the SOUNDEX
values of two very similar strings. For a Latin1_General collation, DIFFERENCE
returns a value of 4
. The second part of the example compares the SOUNDEX
values for two very different strings, and for a Latin1_General collation, DIFFERENCE
returns a value of 0
.
-- 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)