Обсуждение: general questions about joins in queries

Hi,

it's the same , try "EXPLAIN <query>" if you are not sure.

Viktor

Dne pondělí 16 ledna 2006 18:01 Zlatko Matić napsal(a):
> Hello.
> Is it better to use A) or B) ?
>
> A)
>
> SELECT
>  "public"."departments".*,
>  "public"."plants".*,
>  "public"."batches_microbs".*,
>  "public"."results_microbs".*
> FROM
>  "public"."departments",
>  "public"."plants",
>  "public"."batches_microbs",
>  "public"."results_microbs"
> WHERE
>  "plants"."department" = "departments"."department" AND
>  "batches_microbs"."plant" = "plants"."plant" AND
>  "results_microbs"."batch" = "batches_microbs"."batch"
>
> B)
>
> SELECT
>  "public"."departments".*,
>  "public"."plants".*,
>  "public"."batches_microbs".*,
>  "public"."results_microbs".*
> FROM
> public.departments
>   INNER JOIN public.plants ON (public.departments.department =
> public.plants.department) INNER JOIN public.batches_microbs ON
> (public.plants.plant = public.batches_microbs.plant) INNER JOIN
> public.results_microbs ON (public.batches_microbs.batch =
> public.results_microbs.batch)
>
>
> Thanks,
>
> Zlatko