Values

Each of the types mentioned in the data model is a subset of an all-encompassing type called a value.

Comparing and ordering values

While it is unsurprising that a data type can be compared with itself, it may be surprising that different types can also be compared with each other.

RETURN 9 > 1;            // Returns true
RETURN [] > time::now(); // Also returns true

This comparison is possible because every type in SurrealDB is a subset of value, and a comparison of any type with another is also simply a comparison of a value with another value. The order of values from least to greatest is:

• none
• null
• bool
• number
• string
• duration
• datetime
• UUID
• array
• object
• geometry
• bytes
• record

As a result, all of the following return true.

RETURN [
    null > none,
    true > null,
    1 > true,
    'a' > 999999999,
    1s > 'a',
    time::now() > 1s,
    rand::uuid() > time::now(),
    [] > rand::uuid(),
    {} > [],
    (89.0, 89.0) > {},
    <bytes>'Aeon' > (89.0, 89.0),
    person:aeon > <bytes>'Aeon'
];

Being able to compare a value with any other value is what makes SurrealDB’s record range syntax possible. As the least possible value is NONE, a query for the records below that begins with NONE and ends with the .. open range syntax will return everything.

CREATE time_data:['2024-07-23T06:36:56.004Z'];
CREATE time_data:['2024-07-24T06:36:56.014Z'];
CREATE time_data:['2024-07-25T06:36:56.014Z'];
SELECT * FROM time_data:[<datetime>'2024-07-24']..;
SELECT * FROM time_data:[NONE]..;

Inside a schema, the keyword any is used to denote any possible value.

DEFINE FIELD anything ON TABLE person TYPE any;

Values and truthiness

Any value is considered to be truthy if it is not NONE, NULL, or a default value for the data type. A data type at its default value is one that is empty, such as an empty string or array or object, or a number set to 0.

The following example shows the result of the array::all() method, which checks to see if all of the items inside an array are truthy or not.

RETURN array::all(["", 1, 2, 3]); // false because of ""
RETURN array::all([{}, 1, 2, 3]); // false because of {}
RETURN array::all(["SurrealDB", { is_nice_database: true }, 1, 2, 3]);  // true

As the ! operator reverses the truthiness of a value, a doubling of this operator can also be used to check for truthiness.

RETURN [
    !!"Has a value", !!"",             // true, false
    !!true, !!false,                   // true, false
    !!{ is_nice_database: true }, !!{} // true, false
    ];