在单个 sql 查询中查找销售额大于 2000 的订单总数和销售总数

Question

INPUT DATA:

Customer_ID order_number    order_value
1                  1      500
1                  2      300
1                  3      2400
1                  4      2123
2                  5      300
2                  2      2400

Output Data:

Customer ID no. of orders   valuegt2000
1             4                   2
2             2                   1

Answer 1

You can use CASE expression if your DBMS has support for it.

This statement works fine at least in PostgreSQL:

select
  customer_id as "customer id",
  count(order_number) as "no. of orders",
  sum(
    case
      when order_value > 2000 then 1
      else 0
    end
  ) as valuegt2000
from
  my_table
group by
  customer_id