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I have a table in which the foreign key refers to the id of the same table. I need to find the children of the first element that pass me as a parameter, until I reach a certain level.

I need to find all the children of one element.

The first time I had the ID_FK, but after, I 

" ";"ID";"ID_FK";"ISLAST"
"1";"12519";"12518";"N"
"2";"12520";"12518";"N"
"3";"12521";"12518";"N"
"4";"12522";"12518";"N"
"5";"12523";"12518";"N"

But afterwards, I have to find each of the results of the ID column, in the ID_FK field, until I find an S in the ISLAST column.

"ID";"ID_FK";"ISLAST"
"12543";"12519";"N"

Recursive until:

"ID";"ID_FK";"ISLAST"
"12519";"12568";"S"

The result:

" ";"ID";"ID_FK";"ISLAST"
"1";"12519";"555018";"s"
"2";"12520";"112318";"s"
"3";"12521";"128818";"s"
"4";"12522";"133888";"s"
"5";"12523";"125888";"s"

I need a query to do this, to be able to pass it to JPA, or else, a way or some idea of ​​how to do it with JPA directly with Entities and recursion.

KikeSP
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1 Answers1

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JPA does not support recursion.

You will have to use SQL.

Here is the documentation of PostgreSQL and its recursive functionality:

https://www.postgresql.org/docs/current/queries-with.html

And here the documentation of Oracle for recursive queries:

https://docs.oracle.com/cd/B19306_01/server.102/b14200/queries003.htm

Simon Martinelli
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