DIFFERENCE (Transact-SQL)

Returns an integer value that indicates the difference between the SOUNDEX values of two character expressions.

Transact-SQL Syntax Conventions

Syntax

DIFFERENCE ( character_expression , character_expression )

Arguments

• 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.

Return Types

int

Remarks

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.

Examples

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 AdventureWorks;
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)

See Also

Reference

SOUNDEX (Transact-SQL)
String Functions (Transact-SQL)

Help and Information

Getting SQL Server 2005 Assistance