Which preposition to use with schoolday

at Occurrences 2%

Janet had passed part of her schooldays at Chetwynd's; and with her brother Charlie she had also attended Sarah Gailey's private dancing-class (famous throughout Turnhill, Bursley, and Hanbridge) at the same time as Hilda.

of Occurrences 2%

I have quoted these to show that Roman children were not without opportunity even in early schooldays of laying to heart much that might lead them to good and generous conduct in later life, as well as to practical wisdom.

with Occurrences 1%

For instance, my own memory continues to clothe my early schooldays with a kind of sunlit happiness, though I was not only not consciously happy, but distinctly and consciously unhappy.

Which preposition to use with  schoolday