Recursive sql subset query, using connect by
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29-09-2020 - |
Question
I have two tables that look a little like this
AGR_TERR_DEF_TERRS
ID
DEF_ID
TERRITORY_ID (foreign key links to TERRITORIES.ID)
TERRITORIES
ID
NAME
PARENT_ID
(parent_id and id are recursive)
Given two DEF_IDs, I need a function which checks whether the territories of one is a complete subset of the other. I've been playing with CONNECT BY, and INTERSECT, but have written a big mess rather than a useful function.
I'm hoping there will be a (relatively) easy SQL query that works.
Solution
Building on @Tony Andrews answer this would produce zero rows when the territories implied by def_id_1 are a subset of those for def_id_2,
select id from territories start with id in
(select territory_id from agr_terr_def_terrs where def_id = :def_id_1)
connect by parent_id = prior id
minus
select id from territories start with id in
(select territory_id from agr_terr_def_terrs where def_id = :def_id_2)
connect by parent_id = prior id
OTHER TIPS
Given the query to get all the terrories for a given DEF_ID (I'm not quite sure what that is with your tables), DEF_ID A is a subset of DEF_ID B if the following query returns no rows:
select statement for A
MINUS
select statement for B
Does that help?
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