A BETWEEN predicate compares a value with a range of values.

  between-predicate =

  --> value-expr -+--------+-> BETWEEN -+----------------+-+
                  +-> NOT -+            +-> ASYMMETRIC --+ |
                                        +-> SYMMETRIC ---+ |
   +-------------------------------------------------------+
   +-> value-expr AND value-expr --------------------------->

    See the Value_Expressions HELP topic for details on value
    expressions.

    ASYMMETRIC is the default.

    The BETWEEN predicate is a simpler way of representing conditions
    that can be represented using other conditional operators:

    value1 BETWEEN value2 AND value3

    Using the BETWEEN predicate is the same as using the following
    complex predicate:

    value1 >= value2
    AND
    value1 <= value3

    ASYMMETRIC

    By default, the BETWEEN predicate depends on the ordering of the
    values. i.e. the first value expression needed to be less than
    or equal to the second value expression and was evaluated as
    equivalent to: V0 
    following example.

    SQL> select a from t where a between asymmetric 2 and 4;
               A
               2
               3
               4
    3 rows selected

    The following query returns zero matches because the value
    expressions are out of order.

    SQL> select a from t where a between asymmetric 4 and 2;
    0 rows selected

    SYMMETRIC

    This alternate format for BETWEEN allows simpler comparision of
    unordered value expressions, as can be seen in these examples
    which return the same results. This comparision is equivalent to:
    (V0 

    For example:

    SQL> select a from t where a between symmetric 2 and 4;
               A
               2
               3
               4
    3 rows selected
    SQL> select a from t where a between symmetric 4 and 2;
               A
               2
               3
               4
    3 rows selected

    Note that NOT BETWEEN operation also changes when using SYMMETRIC

    This first query using ASYMMETRIC returns all values not in the
    specified range.

    SQL> select a from t where a not between asymmetric 2 and 4;
               A
               1
               5
    2 rows selected

    In this next query the range values is out of order and the
    BETWEEN predicate returns an empty set of matches, and therefore
    NOT BETWEEN returns all rows in the example table.

    SQL> select a from t where a not between asymmetric 4 and 2;
               A
               1
               2
               3
               4
               5
    5 rows selected

    Contrast this to SYMMETRIC which returns the same set of values
    for either ordering of values:

    SQL> select a from t where a not between symmetric 2 and 4;
               A
               1
               5
    2 rows selected
    SQL> select a from t where a not between symmetric 4 and 2;
               A
               1
               5
    2 rows selected