sql - How to load multiple one-to-many relations in Typeorm / PostgreSQL?

Question

I have 3 tables A, B, C.

• A is the main table
• B & C have a many-to-one relation with A

Let's say the data is as follow:

Table A                  Table B                            Table C
|  id   | name  |        |  id   | a_id (FK) | value |      |  id   | a_id (FK) | value |
| :---: | :---: |        | :---: | :-------: | :---: |      | :---: | :-------: | :---: |
|  a0   |  A0   |        |  b0   |    a0     |  B0   |      |  c0   |    a0     |  C0   |
|  a1   |  A1   |        |  b1   |    a0     |  B1   |      |  c1   |    a0     |  C1   |
                         |  b2   |    a1     |  B2   |

I want to retrieve the records in A with their relations aggregated into an array or a json, like so:

id	name	b	c
a0	A0	[[b0, B0], [b1, B1]]	[[c0, C0], [c1, C1]]
a1	A1	[[b2, B2]]	[]

question from:https://stackoverflow.com/questions/65649628/how-to-load-multiple-one-to-many-relations-in-typeorm-postgresql

Answer 1

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