SOUNDEX

• •Uses the first character in string as the first character in the return value and encodes it in uppercase. For example, both SOUNDEX(‘John’) and SOUNDEX(‘john’) return ‘J500’.
• •Encodes the first three unique consonants following the first character in string and ignores the rest. For example, both SOUNDEX(‘JohnRB’) and SOUNDEX(‘JohnRBCD’) return ‘J561’.
• •Assigns a single code to consonants that sound alike.
The following table lists SOUNDEX encoding guidelines for consonants:

Code	Consonant
1	B, P, F, V
2	C, S, G, J, K, Q, X, Z
3	D, T
4	L
5	M, N
6	R

• •Skips the characters A, E, I, O, U, H, and W unless one of them is the first character in string. For example, SOUNDEX(‘A123’) returns ‘A000’ and SOUNDEX(‘MAeiouhwC’) returns ‘M000’.
• •If string produces fewer than four characters, SOUNDEX pads the resulting string with zeroes. For example, SOUNDEX(‘J’) returns ‘J000’.
• •If string contains a set of consecutive consonants that use the same code listed in SOUNDEX, SOUNDEX encodes the first occurrence and skips the remaining occurrences in the set. For example, SOUNDEX(‘AbbpdMN’) returns ‘A135’.
• •Skips numbers in string. For example, both SOUNDEX(‘Joh12n’) and SOUNDEX(‘1John’) return ‘J500’.
• •Returns NULL if string is NULL or if all the characters in string are not letters of the English alphabet.

Syntax

Return Value

• •If value passed to the function is NULL.
• •No character in string is a letter of the English alphabet.
• •string is empty.

Example