Range

Custom range type over a subtype using TYPE name AS RANGE (...).

Basic range type

SCHEMA public {
    TYPE float8range AS RANGE (
        SUBTYPE      = float8,
        SUBTYPE_DIFF = float8mi
    );
}

-- emits
CREATE TYPE "public"."float8range" AS RANGE (
    SUBTYPE      = float8,
    SUBTYPE_DIFF = float8mi
);

Range type with operator class and collation

SCHEMA public {
    TYPE ci_text_range AS RANGE (
        SUBTYPE           = text,
        SUBTYPE_OPCLASS   = text_pattern_ops,
        COLLATION         = "und-u-ks-level2"
    );
}

-- emits
CREATE TYPE "public"."ci_text_range" AS RANGE (
    SUBTYPE         = text,
    SUBTYPE_OPCLASS = text_pattern_ops,
    COLLATION       = "und-u-ks-level2"
);

Any change to a range type’s parameters requires DROP TYPE CASCADE then CREATE TYPE — DESTRUCTIVE.