I came to a problem where mysql thinks that ö=o. So if your tables collation ist utf8_general_ci for example and you do
SELECT * FROM table WHERE some_field LIKE '%ö%'
You will get every row containing an “ö” but you also get every row containing an “o” (and vice versa btw).So if you really want to select the right rows you can go like this:
SELECT * FROM table WHERE some_field LIKE ('%ö%' COLLATE utf8_bin)
Now you only get the rows containing “ö”.