求一SQL语句 - 其他数据库开发 / MySQL/Postgresql

有一订单表
SQL code:
t_orders{
oid,
user_id,
booking_time
}


用户拥有的订单数
SQL code:
select o.user_id, count(o.oid) as amount from t_orders o where booking_time between (time1, between2)
group by o.user_id order by amount

====================
user_id amount
10001 1
10002 1
10004 2
10003 3
10007 3
10009 3
10011 3
10005 5
10006 8
10008 8
10010 8

现需统计拥有订单数目相同的用户数
希望结果：
orderAmount users
1 2
2 1
3 4
5 1
8 3

麻烦哪位帮写下能得出上面统计结果的SQL?

---

SQL code:

select tb.amount,count(*) users from
(select o.user_id, count(o.oid) as amount from t_orders o where booking_time between (time1, between2)
group by o.user_id) tb
group by tb.amount
order by tb.amount;

---

select amount,count(*) as users from 
(select o.user_id, count(o.oid) as amount from t_orders o where booking_time between (time1, between2)
group by o.user_id) t
group by amount
ord