x like y
is evaluated internal as
The function SOUNDEX returns a very simple phonetic picture of a string. Following the rules:
The first letter is taken over without a change.
The following chars are coded from left to right on this way:
'B','F','P','V' -> '1'
'C','G','K','Q','S','X','Z','ß' -> '2'
'D','T' -> '3'
'L' -> '4'
'M','N' -> '5'
'R' -> '6'
All other chars are skipped. A letter is also skipped if it returns the same code like the last one.
Only the first four characters of the resulting string are used.
The disadvantage is that many different words match and a search returns a to big number of hits.
Though SOUNDEX has nothing to do with the operator "HAS", which is based on the function POS again.
If the searched item is not at the beginning of the string you will not have luck with "ähnlich".
Better than "ähnlich" or "enthält" is in all cases the use of "wie" and "in" or of STRCMP (for special applications).