Sql 在Postgres中使用限制1

我有以下sql查询，它在MYSQL上运行良好，但由于最后一个limit 1子句，在Oracle和sql Server上出现错误。我的问题是-根据PostgreSQL，这个limit 1子句有效吗？我能指望它在Postgres上成功运行吗

select customer_number 
from
(select 
customer_number,
count(*) 
from
orders
group by 
customer_number 
order by count(*) desc limit 1) a

---

)

对于

sql server

您需要使用

top

select top 1 customer_number,count(*) 
from orders
group by customer_number 
order by count(*) desc 

---

limit

受某些数据库支持，但并非所有数据库都支持。SQL标准是：

select customer_number
from orders
group by customer_number 
order by count(*) desc 
offset 1 row fetch first 1 row only;