SELECT语句用于WHERE子句中的Count

Question

我正在尝试构造正确的sql语句(Oracle)以获取每个customer_id的device_id的计数大于给定值.例如,我想知道拥有3个以上device_ids的customer_id.单个device_id只能有一个customer_id与之关联,而customer_id可能有许多device_id.

Table:
device_id
customer_id
....

Data (device_id, customer_id):
00001, CUST1
00002, CUST1
00003, CUST1
00004, CUST1
00005, CUST2
00006, CUST2

Answer 1

为了获得超过3台设备的客户:

select customer_id, count(device_id)
from YourTable
Group by customer_id
having count(device_id) > 3