Re: How can I group all children by their parent ?

How can I group all children by their parent ? 

id  email         parent_id
1   test@test.com   nil
2   test1@test.com  1
3   email           1
4   email           2
5   email          nil
6   email           3

 

Regards,
Arup Rakshit

Did you mean
SELECT array_agg(id), array_agg(email), parent_id FROM ... GROUP BY parent_id

id  email         parent_id
[1,5]   [test@test.com,email]   nil
[2,3]   [test1@test.com,email]  1
[4]   [email]           2
[6]   [email]           3

or
SELECT id, email, parentid FROM ... ORDER BY parent_id

id  email         parent_id
1   test@test.com   nil
5   email          nil
2   test1@test.com  1
3   email           1
4   email           2
6   email           3

Regards
Mathieu Pujol