When to open and close brackets surrounding joins in MS Access SQL

Question

I want to understand when to open and close brackets when representing joins in MS Access queries as I am developing a query builder using C++ for MS Access queries so that

Answer 1

Essentially, when an MS Access query references more than two tables, every successive join between a pair of tables should be nested within parentheses.

For example, a query with two tables requires no parentheses:

select *
from a inner join b on a.id = b.id

The addition of a third joined table necessitates parentheses surrounding the original join in order to distinguish it from the additional join:

select *
from 
(
    a inner join b on a.id = b.id
) 
inner join c on a.id = c.id

Every successive addition of a table will then cause the existing joins to be nested within another level of parentheses:

select *
from 
(
    (
        a inner join b on a.id = b.id
    ) 
    inner join c on a.id = c.id
)
inner join d on a.id = d.id

Hence, in general:

select *
from 
(
    (
        (
            (
                table1 [inner/left/right] join table2 on [conditions]
            ) 
            [inner/left/right] join table3 on [conditions]
        )
        [inner/left/right] join table4 on [conditions]
    )
    ...
)
[inner/left/right] join tableN on [conditions]

There is a subtlety where LEFT/RIGHT joins are concerned, in that the order of nesting must maintain the direction of the join, for example:

select *
from 
(
    c left join b on c.id = b.id
) 
left join a on a.id = b.id

Could be permuted to:

select *
from 
c left join
(
    b left join a on b.id = a.id
)
on c.id = b.id