Question

i have the following table structure
table “location” has
– id
– parentLocation_id (relation to itself)
– name

let assume we have the following data:

id  parentLocation_id  name

1         null           Egypt
2          1             Cairo
3          2             Zamalek

here we have three levels of locations , i want to get all levels (locations) that have id =1 or child of location_id.

The result must have all the three locations if i selected Egypt location (get all inheritance level).

i tried the following

select l.id from Location as l where l.id = 1 or l.id in (select id from Location where parentLocation_id= l.id);

here the result is not correct , and here i reached to the second level only.

How can i do this??

Thanks In Advance

Answer 1

Here is another answer that may fit your desired results better. Note that there are three (3) places that you need to put the desired id

SELECT l1.id AS select_id
FROM location l1
WHERE l1.id IN (
    SELECT l2.id 
    FROM location l2, location l3 
    WHERE l2.id = 1 OR l2.parentLocation_id = 1 OR (l2.parentLocation_id = l3.id AND l3.parentLocation_id = 1)
)