This question already has an answer here:
My friends and I applied for a Hungary tourist visa for 7 days and opted for multiple entry. We were planning to be in Budapest for 7 days and another 6 days in Amsterdam.
The thing is, when we got our passport back, it stated 7 days' duration of stay and single entry. We wanted to go to Amsterdam for another 6 days, however. Clearly its not possible as we were only granted 7 days.
Would it be okay to apply for another Schengen visa from the date our Hungarian visa expires? We are planning to go to Hungary from 14th-20th of April 2016 (7 days' duration of stay in the visa), and planning to fly to Amsterdam from Budapest on 20th-26th of April.