Syntax:
SOUNDEX(str)

Returns a soundex string from str. Two strings that sound almost the
same should have identical soundex strings. A standard soundex string
is four characters long, but the SOUNDEX() function returns an
arbitrarily long string. You can use SUBSTRING() on the result to get a
standard soundex string. All non-alphabetic characters in str are
ignored. All international alphabetic characters outside the A-Z range
are treated as vowels.
