I have a nested SQL query, which broadly looks like below,

select distinct A.*, B.col1
from table1 A
left join table2 B
on <<something>>
where A.col1 = <<something>>
group by A.col3, A.col4

My understanding on the sequence of execution is as below

1. Left join A & B on <<something>>
2. Subset resulting table from #1 based on A.col1 = <<something>>
3. Then execute group by A.col3, A.col4
4. Within each group from previous step get distinct combination of A.*, B.col1

Could you please help if above understanding is correct?

What is the general rule for above such nested query?