SQLite - Returning records in a specific month and year in date

I'm trying to get the records with a specific month and year like this:

SELECT * from table where strftime('%m', date) = '?'

if I test this query:

SELECT strftime('%m', date) from table

it return 19, but there's only records with may in month, so I thought the result was 5, but it's 19! Why? What's wrong with my query? How can I return specific records using a specific value for month and year, linke 5 (may) and 2015