MySQL Join AND EXISTS in combination -
case got following query:
select * `parking_parking` join `parking_address` on `parking_parking`.`parking_address` = `parking_address`.`address_id` `parking_id` = 3
this query selects information parking (address , data parking itself)
and in general.. works!
problem
there small problem though.. whenever address has been deleted database , parking still exists. entire query returns 0. because looks , a , b linked. if 1 not found second won't returned either.
now there solution.. exists
however not know how use it.
i tried:
exists join join exists join `parking_address` on exists
but no avail.
i hope (and guess) have overlooked small thing.
note
!! not use in real life! !!
select *
i did 1 when still @ veeeery basics , found out hard way simplest pages took ages load.
solution : goleztrol
select * `parking_parking` left join `parking_address` on `parking_parking`.`parking_address` = `parking_address`.`address_id` `parking_id` = 3
change join
(which short inner join
) left join
(= left outer join
). return parkings , return null
address fields if there no matching address:
select * `parking_parking` left join `parking_address` on `parking_parking`.`parking_address` = `parking_address`.`address_id` `parking_id` = 3
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