SQL Server String SOUNDEX() Function

SQL Server SOUNDEX() Function

The SQL Server SOUNDEX() function is used to return a four-character code that represents the phonetic pronunciation of a string. This function is useful for comparing strings that sound similar but may be spelled differently.

Syntax

SELECT SOUNDEX(string);

The SOUNDEX() function takes a single argument:

  • string: The string for which to generate the SOUNDEX code.

Example SQL Server SOUNDEX() Function Queries

Let's look at some examples of SQL Server SOUNDEX() function queries:

1. Basic SOUNDEX() Example

SELECT SOUNDEX('Smith') AS soundex_code;

This query returns the SOUNDEX code for the string 'Smith'. The result will be:

soundex_code
------------
S530

2. SOUNDEX() with a Column

SELECT first_name, SOUNDEX(first_name) AS soundex_code
FROM employees;

This query returns the SOUNDEX code for the first_name column for each employee. The result will show the first_name and its corresponding SOUNDEX code.

3. SOUNDEX() with a Variable

DECLARE @myString VARCHAR(50);
SET @myString = 'Robert';
SELECT SOUNDEX(@myString) AS soundex_code;

This query uses a variable to store a string and then returns its SOUNDEX code. The result will be:

soundex_code
------------
R163

Full Example

Let's go through a complete example that includes creating a table, inserting data, and using the SOUNDEX() function.

Step 1: Creating a Table

This step involves creating a new table named example_table to store some sample data.

CREATE TABLE example_table (
    id INT PRIMARY KEY,
    name VARCHAR(50)
);

In this example, we create a table named example_table with columns for id and name.

Step 2: Inserting Data into the Table

This step involves inserting some sample data into the example_table.

INSERT INTO example_table (id, name) VALUES (1, 'Smith');
INSERT INTO example_table (id, name) VALUES (2, 'Smyth');
INSERT INTO example_table (id, name) VALUES (3, 'Robert');
INSERT INTO example_table (id, name) VALUES (4, 'Rupert');

Here, we insert data into the example_table.

Step 3: Using the SOUNDEX() Function

This step involves using the SOUNDEX() function to return the SOUNDEX codes for the name column.

SELECT id, name, SOUNDEX(name) AS soundex_code
FROM example_table;

This query retrieves the id, name, and the SOUNDEX code of the name column for each row in the example_table. The result will be:

id  name    soundex_code
--- ------- ------------
1   Smith   S530
2   Smyth   S530
3   Robert  R163
4   Rupert  R163

Conclusion

The SQL Server SOUNDEX() function is a powerful tool for generating a four-character code that represents the phonetic pronunciation of a string. Understanding how to use the SOUNDEX() function and its syntax is essential for effective string comparison and data processing in SQL Server.