On duplicate key update makes duplicate records

insert into views (city, country, views) values (1, 1, 1) on duplicate key update views = views + 1;

create table views

(

    id      int unsigned auto_increment primary key,

    city    int unsigned default 0 not null,

    country int unsigned default 0 not null,

    views   int unsigned default 0 not null,

    constraint listing_month unique (city, country)

)