Advise fails to give covering index for join operation.

ADVISE SELECT t_1.int_field1 , t_1.decimal_field1 , t_1.primary_key_id , t_1.bool_field1
FROM bucket_01 t_1
INNER JOIN bucket_04 t_4
ON ( t_1.primary_key_id = t_4.primary_key_id )
INNER JOIN bucket_04 t_5
ON ( t_1.primary_key_id = t_5.primary_key_id );

This query fails to give covering index recommendation for bucket_01.