Return sequence with distinct values.
The following construct(s) refer to this construct:
fn:distinct-values(atomicValue* $srcval) => atomicValue
fn:distinct-values(atomicValue* $srcval, string $collation) => atomicValue
This function returns the sequence that contains each value at most once
by removing from $srcval all but one of a set of equal
values. All the values must be of a single type or one if its subtypes; numeric
values are promoted to a single common type. Equality must be defined for the
type. If the values are string values, then equality is determined according to
the collation used. If the values are of type xs:double or
xs:float, the values "0.0" and
"-0.0" are considered equal. If values are of type
xs:date or xs:time and have no timezone information,
an implicit timezone is provided by the evaluation context.
If the argument is the empty sequence, the function returns the empty sequence.
You can use an optional collation argument which is used when string comparison is required.
| $srcval |
atomic value |
|---|---|
| $collation |
valid collation string literal |
The following query results only one value of type
xs:time, since both values are equal:
distinct-values((xs:time("10:00:00"), xs:time("11:00:00+01:00")))
The following query results in a type error, since the values of the sequence are not of a single common type:
distinct-values((1, "one"))
Get the names of all doctors, each of them appearing only once in the resulting sequence:
let $a := input()/doctor/name/surname return distinct-values($a)