Find a master and child table join query, please help, online, etc.

用户名1

There are two tables:
1. parent table; 2. child table

parent primary key: id
child primary key: id, foreign key p_id

Now you need to query the parent records and sort them. The sorting principle is based on the number of subtables corresponding to each main table record. The main table records with subtable records of 0 must also be displayed.

talentzj

select *
from parent as p left outer join child as c
on p.id = c.id
order by c.id asc

用户名1

totalentzj:

I think I will describe it clearly. The principle of sorting the main table is to sort by the number of records in the subtable p_id corresponding to the main table ID. E.g:
parent record: id name memo
             1 1 1
             2 2 2
child record: id name memo p_id
             1 c1 c1 1
             2 c2 c2 2
             3 c3 c3 2

The query results are: id name memo
                  2 2 2
                  1 1 1

noendenergy

select id, name, memo from parent where id in (select pid from child) group by id order by id desc;