mysql - Join tables keeping empty results -

i have 2 tables need cross , return many results ids of 1 of them.

the first table of roles/tasks:

id | rolename ---+--------- 1  | check_in 2  | cleaning 3  | taxi 4  | guide 5  | car_rental 6  | meals 7  | house_owner 20 | custom 

and table has columns:

id | client_booking_id | staff_role_id | confirmed | staff_cost 

i need query gives me many results nr of columns in first table. because each unique client_booking_id there 1 (if any) of tasks/roles.

so if do:

select sr.role_name, sr.id, ss.staff_cost, ss.confirmed      staff_role sr     left join staff_schedule ss on sr.id=ss.staff_role_id 

i result nr of rows want. need match specific client_booking_id did

select sr.role_name, sr.id, ss.staff_cost, ss.confirmed      staff_role sr     left join staff_schedule ss on sr.id=ss.staff_role_id     ss.client_booking_id=1551 // <-- new line 

and gives me 2 results because in second table have booked 2 tasks id.

but need result tasks not match, null values. how can this?

with query (without where clause) rows null , non-null values client_booking_id. want match specific client_booking_id , @ same time leave records null values, add additional condition specific client_booking_id left join.

moving condition left join:

select sr.role_name      , sr.id      , ss.staff_cost      , ss.confirmed  staff_role sr left join staff_schedule ss on sr.id = ss.staff_role_id                            , ss.client_booking_id = 1551