Hi Justin,
you have redundancy in your data. You have "fee" different for a single student id in your second table. So when you will use left join to fetch merged data, you will get duplicates. Because of there is no way to track which row you've inserted last, you go with two options: first remove the duplicate entries, second you should add a column to record timestamp for every entry & then you would be able to get the unique values without removing duplicates:
for the first option, I've created a sample query for you:
I've assumed your tables as s1 and s2 accordingly.
select s1.studentid, s1.studentname, s1.address, s1.dob, s2.class, s2.fee, s2.isactive
from s1 left join s2 on s1.studentid=s2.studentid;
Hope this helps!
Happy Coding :)
Sunny_K