AppDividend
Latest Code Tutorials

SQL DIFFERENCE() Function: The Complete Guide

SQL DIFFERENCE() is one of the String Functions, compares two SOUNDEX values, and returns the integer. An integer value indicates the match for the two SOUNDEX values, 0 to 4. The 0 shows weak or no similarity between the SOUNDEX values. The 4 indicates strong similarity or identically SOUNDEX values.

SQL DIFFERENCE()

SQL DIFFERENCE() is a built-in function used to return the difference between the Soundex values. The Soundex value is four characters long. If two strings sound the same, their Soundex values will be the same. However, if two strings sound entirely different, none of the character’s Soundex values will be the same.

For example, peace and piece sound the same to have the same Soundex values.

SELECT SOUNDEX ('piece') AS Piece, SOUNDEX ('Peace') AS Peace;

See the output.

Piece Peace
P200 P200

 

See the following syntax.

SELECT DIFFERENCE (input_string1, input_string2);

Parameters

  1. DIFFERENCE: Used for comparing two Soundex values.
  2. Input_string1, input_string_2: Strings whose Soundex values are to be considered.

Examples

  1. STRONG SIMILARITY

Query

SELECT SOUNDEX('PIECE') AS PIECE, SOUNDEX('PEACE') AS PEACE, DIFFERENCE ('PIECE', 'PEACE') 
AS SIMILARITY;

Output

As the Soundex values of both the strings are the same and there is a strong similarity between them, 4 is returned.

Query

SELECT SOUNDEX (‘TWO’) AS TWO, SOUNDEX(‘TOO’) AS TOO, DIFFERENCE (‘TWO’, ‘TOO’) AS SIMILARITY;

Output

TWO TOO SIMILARITY
T000 T000 4

 

Less Similarity

See the following query.

SELECT SOUNDEX (‘COFFEE’) AS COFEE, SOUNDEX(‘LAPTOP’) AS LAPTOP, DIFFERENCE (‘COFFEE’, ‘LAPTOP’) 
AS SIMILARITY;

Output

COFFEE LAPTOP SIMILARITY
C100 L131 1

 

In the above query, both the strings, sounds were different, so there was a minimal similarity between the two strings. Therefore, 1 was returned as output because 1 character of Soundex values had a match.

No Similarity

Query

SELECT SOUNDEX('Tree') AS Tree, SOUNDEX('Captivated') AS Captivated, DIFFERENCE ('Tree', 'Captivated') 
AS SIMILARITY;

Output

Tree Captivated SIMILARITY
T600 C131 0

 

In the above output, there is no match between any characters. So, the value returned was 0.

That’s it for this tutorial.

Recommended Posts

SQL CHARINDEX Function

Subqueries In SQL

Alias In SQL

SQL TOP, LIMIT Or ROWNUM Clause

What Is SQL Injection

Leave A Reply

Your email address will not be published.

This site uses Akismet to reduce spam. Learn how your comment data is processed.