This question already has an answer here:
I am a Bangladeshi citizen and came on April 18th, 2017 to watch a football match in Spain. My spanish Schengen visa expires (today) on April, 21th 2017 and I am currently travelling to Germany from Spain by car, but I am still in Spain now. My German Schengen visa starts from April 22th, 2017 and is valid for a year, but I want to go back to Bangladesh on April 30th, 2017.
So do I need to leave the Schengen area today and come back tomorrow to Germany or does the German visa allows me to remain in the Schengen area?