mysql - get rows from two tables using join and sub query -


i have table of persons

person_id , person_name

another table of person_vehicle_relation

pv_id , person_id , vehicle_id, role

i want build query in can list of

pv_id , person_name

where vehicle_id= 3 , role = 'driver'.

i have tried join in following way not working. how can desired data?

select persons.person_name , person_vehicle_relation.pv_id  persons    inner join person_vehicle_relations on persons.person_id = (select person_id person_vehicle_relations vehicle_id = 3 , role= 'driver')

and error

msg 512, level 16, state 1, line 1 subquery returned more 1 value. not permitted when subquery follows =, !=, <, <= , >, >= or when subquery used expression.

why need subquery/inline view? simple should work.

select p.person_name , pvr.pv_id persons p inner join person_vehicle_relations  pvr    on p.person_id = prv.person_id pvr.vehicle_id = 3    , pvr.role= 'driver'

the reason why had error because subquery returned multiple persons , single person_id person's can't match multiple persons pvr.

you switch "in" instead of "=" , should work well; join , clause seemed simplest maintain , run.

one joins on pk/fk relationship applies limits in or in having. use subquery/inline views instead of straight join when need aggregation done , m-m relationship artificially inflate aggregation. may use subqueries in cross applies or in exists when don't need data second table. in case needed data both tables join seemed best.


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