Function reverse 

pub fn reverse<'a, V, E>(
    expr: E,
) -> SQLExpr<'a, V, <V::DialectMarker as DialectTypes>::Text, E::Nullable, E::Aggregate>
where
    V: SQLParam + 'a,
    V::DialectMarker: ReverseSupport,
    E: Expr<'a, V>,
    E::SQLType: Textual,

REVERSE - reverses a string (PostgreSQL and MySQL).

Preserves the nullability of the input expression.