Function age 

pub fn age<'a, V, E1, E2>(
    timestamp1: E1,
    timestamp2: E2,
) -> SQLExpr<'a, V, Interval, <E1::Nullable as NullOr<E2::Nullable>>::Output, <E1::Aggregate as AggOr<E2::Aggregate>>::Output>
where
    V: SQLParam + 'a,
    V::DialectMarker: PostgresDateTimeSupport,
    E1: Expr<'a, V>,
    E1::SQLType: Temporal,
    E2: Expr<'a, V>,
    E2::SQLType: Temporal,
    E1::Nullable: NullOr<E2::Nullable>,
    E2::Nullable: Nullability,
    E1::Aggregate: AggOr<E2::Aggregate>,

AGE - calculates the interval between two timestamps (PostgreSQL).

Returns PostgreSQL INTERVAL. The result is nullable if either input is nullable.

Example

use drizzle_core::expr::age;

// SELECT AGE(NOW(), users.created_at)
let user_age = age(now(), users.created_at);