By default the the BETWEEN operator requires the lower bound and upper bound to be "in order"

select *
from foo
where id between 42 and 24;

will not return anything. When using BETWEEN SYMMETRIC, the order is irrelevant.

The following query will return all rows that satisfy the condition id >= 24 and id <= 42

select *
from foo
where id between symmetric 42 and 24;

Back to the SQL Feature Comparison