Change all year tags to format yyyy

Hi, I have tried to search for this without luck. After importing a fair share of albums I have noticed that many of the albums now have dates inserted into the year field in the format yyyy-mm-dd. Is there a good way to change it so that I only get the year as yyyy without the date? I would also like to do it with my whole database.

Thanks in advance for any tips!

Try setting the month and day fields to zero, with a command similar to beet modify month=0.