Practice Activity: What rows in an SQL Server table are not included in a second table?

[@user-qj1ht1bv5x]

4:27 WHY NOT JUST USE JOIN?
select * from FirstTable as t1
left join SecondTable as t2
on t1.ID=t2.ID
;

[@SQLServer101]

Hi. That is a good start, but that will show all rows in t1 (and where they exist in t2). However, I want to find all of those which are in t1 but not in t2. Phillip