Range Functions and Operators
Ranges represent some interval of values. The intervals can include or exclude their boundaries or can even omit one or both boundaries. Only some scalar types have corresponding range types:
-
range<int32>
-
range<int64>
-
range<float32>
-
range<float64>
-
range<decimal>
-
range<datetime>
-
range<cal::local_datetime>
-
range<cal::local_date>
Constructing ranges
There’s a special range()
constructor function for making range
values. This is a little different from how scalars, arrays and tuples are
created typically in EdgeDB.
For example:
db>
select range(1, 10);
{range(1, 10)}
db>
select range(2.2, 3.3);
{range(2.2, 3.3)}
Broadly there are two kinds of ranges: discrete
and
contiguous
. The discrete ranges are
range<int32>
, range<int64>
, and range<cal::local_date>
. All ranges
over discrete types get normalized such that the lower bound is included
(if present) and the upper bound is excluded:
db>
select range(1, 10) = range(1, 9, inc_upper := true);
{true}
db>
select range(1, 10) = range(0, 10, inc_lower := false);
{true}
Ranges over contiguous types don’t have the same normalization mechanism because the underlying types don’t have granularity which could be used to easily include or exclude a boundary value.
Sometimes a range cannot contain any values, this is called an empty range. These kinds of ranges can arise from performing various operations on them, but they can also be constructed. There are basically two equivalent ways of constructing an empty range. It can be explicitly constructed by providing the same upper and lower bounds and specifying that at least one of them is not inclusive (which is the default for all range constructors):
db>
select range(1, 1);
{range({}, inc_lower := false, empty := true)}
Alternatively, it’s possible to specify {}
as a boundary and also provide
the empty := true
named-only argument. If the empty set is provided as a
literal, it also needs to have a type cast, to specify which type of the range
is being constructed:
db>
select range(<int64>{}, empty := true);
{range({}, inc_lower := false, empty := true)}
Since empty ranges contain no values, they are all considered to be equal to each other (as long as the types are compatible):
db>
select range(1, 1) = range(<int64>{}, empty := true);
{true}
db>
select range(1, 1) = range(42.0, 42.0);
{true}
db>
select range(1, 1) = range(<cal::local_date>{}, empty := true);
error: InvalidTypeError: operator '=' cannot be applied to operands of type 'range<std::int64>' and 'range<cal::local_date>' ┌─ query:1:8 │ 1 │ select range(1, 1) = range(<cal::local_date>{}, empty := true); │ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Consider using an explicit type cast or a conversion function.
JSON representation
Much like arrays and tuples, the
range types cannot be directly cast to a str
, but instead can be
cast into a json
structure:
db>
select <json>range(1, 10);
{"inc_lower": true, "inc_upper": false, "lower": 1, "upper": 10}
It’s also possible to cast in the other direction - from json
to a
specific range type:
db> ... ... ... ... ...
select <range<int64>>to_json('{
"lower": 1,
"inc_lower": true,
"upper": 10,
"inc_upper": false
}');
{range(1, 10)}
Empty ranges have a shorthand json
representation:
db>
select <json>range(<int64>{}, empty := true);
{"empty": true}
When casting from json
to an empty range, all other fields may be
omitted, but if they are present, they must be consistent with an empty range:
db>
select <range<int64>>to_json('{"empty": true}');
{range({}, inc_lower := false, empty := true)}
db> ... ... ... ... ...
select <range<int64>>to_json('{
"lower": 1,
"inc_lower": true,
"upper": 1,
"inc_upper": false
}');
{range({}, inc_lower := false, empty := true)}
db> ... ... ... ... ... ...
select <range<int64>>to_json('{
"lower": 1,
"inc_lower": true,
"upper": 1,
"inc_upper": false,
"empty": true
}');
{range({}, inc_lower := false, empty := true)}
db> ... ... ... ... ... ...
select <range<int64>>to_json('{
"lower": 1,
"inc_lower": true,
"upper": 2,
"inc_upper": false,
"empty": true
}');
edgedb error: InvalidValueError: conflicting arguments in range constructor: "empty" is ``true`` while the specified bounds suggest otherwise
When casting from json
to a range the lower
and upper
fields are optional, but the inclusivity fields inc_lower
and
inc_upper
are mandatory. This is to address the fact that whether the
range boundaries are included by default can vary based on system or context
and being explicit avoids subtle errors. The only exception to this are
empty ranges that can have just the "empty": true
field.
Multiranges
Intermittent availability or ranges with gaps can be naturally represented by
a set of ranges. However, using a multirange()
for this purpose is
even better. At its core a multirange is a set of ranges packaged together
so that it’s easy to perform range operations on the whole set:
db>
select multirange([range(1, 5), range(8,10)]);
{[range(1, 5), range(8, 10)]}
db>
select contains(multirange([range(1, 5), range(8,10)]), 9);
true
Another advantage of a multirange is that its components are always automatically ordered and normalized to be non-overlapping, even if it’s constructed from an array of ranges that don’t satisfy either of these conditions:
db>
select multirange([range(8, 10), range(1, 4), range(2, 5)]);
{[range(1, 5), range(8, 10)]}
Multiranges are compatible with ranges for the purpose of most operations, making it more conveninet to manipulate them whenever you have more than one range to work with:
db>
select multirange([range(8, 10)]) + range(1, 5) - range(3, 4);
{[range(1, 3), range(4, 5), range(8, 10)]}
Functions and operators
One range or multirange is before the other. | |
One range or multirange is after the other. | |
One range or multirange is before or same as the other. | |
One range or multirange is after or same as the other. | |
Range or multirange union. | |
Range or multirange subtraction. | |
Range or multirnage intersection. | |
Construct a range. | |
Return lower bound value. | |
Return upper bound value. | |
Check whether lower bound is inclusive. | |
Check whether upper bound is inclusive. | |
Check whether a range is empty. | |
Return values from a range. | |
Check if an element or a range is within another range. | |
Check whether ranges or multiranges overlap. | |
Check whether ranges or multiranges share a boundary without overlapping. | |
All values of the first range or multirange appear after the second. | |
All values of the first range or multirange appear before the second. | |
The first argument is bounded above by the upper bound of the second. | |
The first argument is bounded below by the lower bound of the second. | |
Construct a multirange. | |
Returns the sub-ranges of a multirange as a set or ranges. |
Reference
One range or multirange is before the other.
Returns true
if the lower bound of the first range or multirange is
smaller than the lower bound of the second range or multirange. The
unspecified lower bound is considered to be smaller than any specified
lower bound. If the lower bounds are equal then the upper bounds are
compared. Unspecified upper bound is considered to be greater than any
specified upper bound.
db>
select range(1, 10) < range(2, 5);
{true}
db>
select range(1, 10) < range(1, 15);
{true}
db>
select range(1, 10) < range(1);
{true}
db>
select range(1, 10) < range(<int64>{}, 10);
{false}
db> ...
select multirange([range(2, 4), range(5, 7)]) <
multirange([range(7, 10), range(20)]);
{true}
An empty range is considered to come before any non-empty range.
db>
select range(1, 10) < range(10, 10);
{false}
db>
select range(1, 10) < range(<int64>{}, empty := true);
{false}
db> ...
select multirange(<array<range<int64>>>[]) <
multirange([range(7, 10), range(20)]);
{true}
This is also how the order by
clauses compares ranges.
One range or multirange is after the other.
Returns true
if the lower bound of the first range or multirange is
greater than the lower bound of the second range or multirange. The
unspecified lower bound is considered to be smaller than any specified
lower bound. If the lower bounds are equal then the upper bounds are
compared. Unspecified upper bound is considered to be greater than any
specified upper bound.
db>
select range(1, 10) > range(2, 5);
{false}
db>
select range(1, 10) > range(1, 5);
{true}
db>
select range(1, 10) > range(1);
{false}
db>
select range(1, 10) > range(<int64>{}, 10);
{true}
db> ...
select multirange([range(2, 4), range(5, 7)]) >
multirange([range(7, 10), range(20)]);
{false}
An empty range is considered to come before any non-empty range.
db>
select range(1, 10) > range(10, 10);
{true}
db>
select range(1, 10) > range(<int64>{}, empty := true);
{true}
db> ...
select multirange(<array<range<int64>>>[]) >
multirange([range(7, 10), range(20)]);
{false}
This is also how the order by
clauses compares ranges.
One range or multirange is before or same as the other.
Returns true
if the ranges or multiranges are identical or if the
lower bound of the first one is smaller than the lower bound of the second
one. The unspecified lower bound is considered to be smaller than any
specified lower bound. If the lower bounds are equal then the upper bounds
are compared. Unspecified upper bound is considered to be greater than any
specified upper bound.
db>
select range(1, 10) <= range(1, 10);
{true}
db>
select range(1, 10) <= range(2, 5);
{true}
db>
select range(1, 10) <= range(1, 15);
{true}
db>
select range(1, 10) <= range(1);
{true}
db>
select range(1, 10) <= range(<int64>{}, 10);
{false}
db> ...
select multirange([range(2, 4), range(5, 7)]) <=
multirange([range(7, 10), range(20)]);
{true}
db> ...
select multirange([range(2, 4), range(5, 7)]) <=
multirange([range(5, 7), range(2, 4)]);
{true}
An empty range is considered to come before any non-empty range.
db>
select range(1, 10) <= range(10, 10);
{false}
db>
select range(1, 1) <= range(10, 10);
{true}
db>
select range(1, 10) <= range(<int64>{}, empty := true);
{false}
db> ...
select multirange(<array<range<int64>>>[]) <=
multirange([range(7, 10), range(20)]);
{true}
This is also how the order by
clauses compares ranges.
One range or multirange is after or same as the other.
Returns true
if the ranges or multiranges are identical or if the
lower bound of the first one is greater than the lower bound of the second
one. The unspecified lower bound is considered to be smaller than any
specified lower bound. If the lower bounds are equal then the upper bounds
are compared. Unspecified upper bound is considered to be greater than any
specified upper bound.
db>
select range(1, 10) >= range(2, 5);
{false}
db>
select range(1, 10) >= range(1, 10);
{true}
db>
select range(1, 10) >= range(1, 5);
{true}
db>
select range(1, 10) >= range(1);
{false}
db>
select range(1, 10) >= range(<int64>{}, 10);
{true}
db> ...
select multirange([range(2, 4), range(5, 7)]) >=
multirange([range(7, 10), range(20)]);
{false}
db> ...
select multirange([range(2, 4), range(5, 7)]) >=
multirange([range(5, 7), range(2, 4)]);
{true}
An empty range is considered to come before any non-empty range.
db>
select range(1, 10) >= range(10, 10);
{true}
db>
select range(1, 1) >= range(10, 10);
{true}
db>
select range(1, 10) >= range(<int64>{}, empty := true);
{true}
db> ...
select multirange(<array<range<int64>>>[]) >=
multirange([range(7, 10), range(20)]);
{false}
This is also how the order by
clauses compares ranges.
Range or multirange union.
Find the union of two ranges as long as the result is a single range without any discontinuities inside.
db>
select range(1, 10) + range(5, 15);
{range(1, 15)}
db>
select range(1, 10) + range(5);
{range(1, {})}
If one of the arguments is a multirange, find the union and normalize the result as a multirange.
db> ... ...
select range(1, 3) + multirange([
range(7, 10), range(20),
]);
{[range(1, 3), range(7, 10), range(20, {})]}
db> ...
select multirange([range(2, 4), range(5, 8)]) +
multirange([range(6, 10), range(20)]);
{[range(2, 4), range(5, 10), range(20, {})]}
Range or multirange subtraction.
Subtract one range from another. This is only valid if the resulting range does not have any discontinuities inside.
db>
select range(1, 10) - range(5, 15);
{range(1, 5)}
db>
select range(1, 10) - range(<int64>{}, 5);
{range(5, 10)}
db>
select range(1, 10) - range(0, 15);
{range({}, inc_lower := false, empty := true)}
If one of the arguments is a multirange, treat both arguments as multiranges and perform the multirange subtraction.
db> ...
select multirange([range(1, 10)]) -
range(4, 6);
{[range(1, 4), range(6, 10)]}
db> ...
select multirange([range(1, 10)]) -
multirange([range(2, 3), range(5, 6), range(9)]);
{[range(1, 2), range(3, 5), range(6, 9)]}
db> ...
select multirange([range(2, 3), range(5, 6), range(9, 10)]) -
multirange([range(-10, 0), range(4, 8)]);
{[range(2, 3), range(9, 10)]}
Range or multirnage intersection.
Find the intersection of two ranges or multiranges.
db>
select range(1, 10) * range(5, 15);
{range(5, 10)}
db>
select range(1, 10) * range(-15, 15);
{range(1, 10)}
db>
select range(1) * range(-15, 15);
{range(1, 15)}
db>
select range(10) * range(<int64>{}, 1);
{range({}, inc_lower := false, empty := true)}
db> ...
select multirange([range(1, 10)]) *
multirange([range(0, 3), range(5, 6), range(9)]);
{[range(1, 3), range(5, 6), range(9, 10)]}
db> ...
select multirange([range(2, 3), range(5, 6), range(9, 10)]) *
multirange([range(-10, 0), range(4, 8)]);
{[range(5, 6)]}
Construct a range.
Either one of lower or upper bounds can be set to {}
to indicate
an unbounded interval.
By default the lower bound is included and the upper bound is excluded from the range, but this can be controlled explicitly via the inc_lower and inc_upper named-only arguments.
db>
select range(1, 10);
{range(1, 10)}
db>
select range(1.5, 7.5, inc_lower := false);
{range(1.5, 7.5, inc_lower := false)}
Finally, an empty range can be created by using the empty named-only
flag. The first argument still needs to be passed as an {}
so that the
type of the range can be inferred from it.
db>
select range(<int64>{}, empty := true);
{range({}, inc_lower := false, empty := true)}
Return lower bound value.
Return the lower bound of the specified range or multirange.
db>
select range_get_lower(range(1, 10));
{1}
db>
select range_get_lower(range(1.5, 7.5));
{1.5}
db> ...
select range_get_lower(
multirange([range(5, 10), range(2, 3)]));
{2}
Check whether lower bound is inclusive.
Return true
if the lower bound is inclusive and false
otherwise.
If there is no lower bound, then it is never considered inclusive.
db>
select range_is_inclusive_lower(range(1, 10));
{true}
db> ...
select range_is_inclusive_lower(
range(1.5, 7.5, inc_lower := false));
{false}
db>
select range_is_inclusive_lower(range(<int64>{}, 10));
{false}
db> ... ... ... ... ...
select range_is_inclusive_lower(
multirange([
range(2, 3),
range(5, 10),
])
);
{true}
Return upper bound value.
Return the upper bound of the specified range or multirange.
db>
select range_get_upper(range(1, 10));
{10}
db>
select range_get_upper(range(1.5, 7.5));
{7.5}
db> ...
select range_get_upper(
multirange([range(5, 10), range(2, 3)]));
{10}
Check whether upper bound is inclusive.
Return true
if the upper bound is inclusive and false
otherwise.
If there is no upper bound, then it is never considered inclusive.
db>
select range_is_inclusive_upper(range(1, 10));
{false}
db> ...
select range_is_inclusive_upper(
range(1.5, 7.5, inc_upper := true));
{true}
db>
select range_is_inclusive_upper(range(1));
{false}
db> ... ... ... ... ...
select range_is_inclusive_upper(
multirange([
range(2.0, 3.0),
range(5.0, 10.0, inc_upper := true),
])
);
{true}
Check whether a range is empty.
Return true
if the range or multirange contains no values and
false
otherwise.
db>
select range_is_empty(range(1, 10));
{false}
db>
select range_is_empty(range(1, 1));
{true}
db>
select range_is_empty(range(<int64>{}, empty := true));
{true}
db>
select range_is_empty(multirange(<array<range<int64>>>[]));
{true}
db>
select range_is_empty(multirange([range(1, 10)]));
{false}
Return values from a range.
For a range of discrete values this function when called without indicating a step value simply produces a set of all the values within the range, in order.
db>
select range_unpack(range(1, 10));
{1, 2, 3, 4, 5, 6, 7, 8, 9}
db> ... ...
select range_unpack(range(
<cal::local_date>'2022-07-01',
<cal::local_date>'2022-07-10'));
{ <cal::local_date>'2022-07-01', <cal::local_date>'2022-07-02', <cal::local_date>'2022-07-03', <cal::local_date>'2022-07-04', <cal::local_date>'2022-07-05', <cal::local_date>'2022-07-06', <cal::local_date>'2022-07-07', <cal::local_date>'2022-07-08', <cal::local_date>'2022-07-09', }
For any range type a step value can be specified. Then the values will be picked from the range, starting at the lower boundary (skipping the boundary value itself if it’s not included in the range) and then producing the next value by adding the step to the previous one.
db>
select range_unpack(range(1.5, 7.5), 0.7);
{1.5, 2.2, 2.9, 3.6, 4.3, 5, 5.7, 6.4}
db> ... ... ... ... ...
select range_unpack(
range(
<cal::local_datetime>'2022-07-01T00:00:00',
<cal::local_datetime>'2022-12-01T00:00:00'
),
<cal::relative_duration>'25 days 5 hours');
{ <cal::local_datetime>'2022-07-01T00:00:00', <cal::local_datetime>'2022-07-26T05:00:00', <cal::local_datetime>'2022-08-20T10:00:00', <cal::local_datetime>'2022-09-14T15:00:00', <cal::local_datetime>'2022-10-09T20:00:00', <cal::local_datetime>'2022-11-04T01:00:00', }
Check whether ranges or multiranges overlap.
Return true
if the ranges or multiranges have any elements in common
and false
otherwise.
db>
select overlaps(range(1, 10), range(5));
{true}
db>
select overlaps(range(1, 10), range(10));
{false}
db> ... ... ... ... ... ... ...
select overlaps(
multirange([
range(1, 4), range(7),
]),
multirange([
range(-1, 2), range(8, 10),
]),
);
{true}
db> ... ... ... ... ... ... ...
select overlaps(
multirange([
range(1, 4), range(7),
]),
multirange([
range(-1, 1), range(5, 6),
]),
);
{false}
Check whether ranges or multiranges share a boundary without overlapping.
db>
select adjacent(range(1, 3), range(3, 4));
{true}
db>
select adjacent(range(1.0, 3.0), range(3.0, 4.0));
{true}
db> ...
select adjacent(
range(1.0, 3.0, inc_upper := true), range(3.0, 4.0));
{false}
db> ... ... ... ... ... ... ...
select adjacent(
multirange([
range(2, 4), range(5, 7),
]),
multirange([
range(7, 10), range(20),
]),
);
{true}
Since range values can be implicitly cast into multiranges, you can mix the two types:
db> ... ... ... ... ...
select adjacent(
range(7),
multirange([
range(1, 2), range(3, 7),
]),
);
{true}
All values of the first range or multirange appear after the second.
db> ... ...
select strictly_above(
range(7), range(1, 5)
);
{true}
db> ... ...
select strictly_above(
range(3, 7), range(1, 5)
);
{false}
db> ... ... ... ... ... ... ...
select strictly_above(
multirange([
range(2, 4), range(5, 7),
]),
multirange([
range(-5, -2), range(-1, 1),
]),
);
{true}
Since range values can be implicitly cast into multiranges, you can mix the two types:
db> ... ... ... ... ...
select strictly_above(
range(8),
multirange([
range(1, 2), range(3, 7),
]),
);
{true}
All values of the first range or multirange appear before the second.
db> ... ...
select strictly_below(
range(1, 3), range(7)
);
{true}
db> ... ...
select strictly_below(
range(1, 7), range(3)
);
{false}
db> ... ... ... ... ... ... ...
select strictly_below(
multirange([
range(-1, 0), range(-5, -3),
]),
multirange([
range(1, 4), range(7),
]),
);
{true}
Since range values can be implicitly cast into multiranges, you can mix the two types:
db> ... ... ... ... ...
select strictly_below(
range(-1, 0),
multirange([
range(1, 4), range(7),
]),
);
{true}
The first argument is bounded above by the upper bound of the second.
db> ... ...
select bounded_above(
range(1, 7), range(3, 7)
);
{true}
db> ... ...
select bounded_above(
range(1, 7), range(3, 6)
);
{false}
db> ... ...
select bounded_above(
range(1, 7), range(3)
);
{true}
db> ... ... ... ... ... ... ...
select bounded_above(
multirange([
range(-1, 0), range(5, 7),
]),
multirange([
range(1, 2), range(3, 7),
]),
);
{true}
Since range values can be implicitly cast into multiranges, you can mix the two types:
db> ... ... ... ... ...
select bounded_above(
range(-1, 10),
multirange([
range(1, 4), range(7),
]),
);
{true}
The first argument is bounded below by the lower bound of the second.
db> ... ...
select bounded_below(
range(1, 7), range(3, 6)
);
{false}
db> ... ...
select bounded_below(
range(1, 7), range(0, 6)
);
{true}
db> ... ... ... ... ... ... ...
select bounded_below(
multirange([
range(-1, 0), range(5, 7),
]),
multirange([
range(1, 2), range(3, 7),
]),
);
{false}
Since range values can be implicitly cast into multiranges, you can mix the two types:
db> ... ... ... ... ...
select bounded_below(
range(5, 7),
multirange([
range(1, 2), range(3, 7),
]),
);
{true}
Construct a multirange.
Construct a multirange from the ranges array. Normalize the sub-ranges so that they become ordered and non-overlapping.
db>
select multirange([range(8, 10), range(1, 4), range(2, 5)]);
{[range(1, 5), range(8, 10)]}
If either an empty array or an empty range is used to construct a multirange, the resulting multirange will be empty. An empty multirange is semantically similar to an empty range.
db> ... ... ... ...
with
a := multirange(<array<range<int64>>>[]),
b := multirange([range(<int64>{}, empty := true)]),
c := range(<int64>{}, empty := true),
select (a = b, b = c);
{(true, true)}
Returns the sub-ranges of a multirange as a set or ranges.
db> ... ... ... ...
select multirange_unpack(
multirange([
range(1, 4), range(7), range(3, 5)
]),
);
{range(1, 5), range(7, {})}
db> ...
select multirange_unpack(
multirange(<array<range<int64>>>[]));
{}