When an operation is associative, the grouping of elements does not matter.
Addition and multiplication are both associative. You can add brackets or remove brackets. The result is always the same.
Associative SQL Joins
SQL Joins are associative when they are of the same type
Inner Join Only
(A INNER JOIN B) INNER JOIN C = A INNER JOIN (B INNER JOIN C)
Left Join Only
(A LEFT JOIN B) LEFT JOIN C = A LEFT JOIN (B LEFT JOIN C)