Forgot: 'word' is a field in table 'words' in this example.
I think you need something like follows. I have table 'words' (in MysQL), which contains single words, and string $sentence='Sentence which contains few words'. To find, which words in $sentence i have also in table, use query like follows:
SELECT * FROM words WHERE '$sentence' LIKE concat('%',word,'%');
The trick is in order of the syntax, expression must be before 'LIKE' and pattern after it.