I have the following table structure:

user:      user_id|user_name
           1      |John Doe
           2      |Alex

data:      data_id|data_kind|data_value
           1      |123      |Hello
           2      |456      |World
           3      |123      |GoodBye
UNIQUE(data_kind, data_value)

user_data: user_id|data_id
           1      |1
           1      |2
           2      |3
           2      |2
UNIQUE(user_id, data_id)

How would I be able to query all users (John Doe) which have (data_kind=123,data_value=’Hello’) and (data_kind=456,data_value=’World’) ?