NTILE example throws: ERROR 1140 (42000): Mixing of GROUP columns (MIN(),MAX(),COUNT(),...) with no GROUP columns is illegal if there is no GROUP BY clause

create table t1 (

    pk int primary key,

    a int,

    b int

  );

insert into t1 values

    (11 , 0, 10),

    (12 , 0, 10),

    (13 , 1, 10),

    (14 , 1, 10),

    (18 , 2, 10),

    (15 , 2, 20),

    (16 , 2, 20),

    (17 , 2, 20),

    (19 , 4, 20),

    (20 , 4, 20);

select pk, a, b,

    ntile(1) over (order by pk)

  from t1;