按每个值计入 mysql

Question

我的table：

 salesName    |    customerName    |     OrderNumber    |
 A            |        H           |          01        |
 A            |        H           |          02        |       
 A            |        I           |          03        |

 B            |        J           |          04        |
 B            |        J           |          05        |
 B            |        J           |          06        |
 B            |        K           |          07        |
 B            |        K           |          08        |
 B            |        L           |          09        |

如何获得此输出：

了解销售业绩，每个客户的总客户数（销售额）， 他们的客户有多少订单

salesName  |  customer  |  order
   A       |     2      |    3
   B       |     3      |    6

提前致谢

Answer 1

使用count(distinct):

select salesname, count(distinct customername) as num_customers,
       count(*) as num_orders
from t
group by salesname;