SQL计数组数

Question

我有一个托盘,物品,物品数量的表:

pallet | item | qty
-------------------
  1        1     2
  1        2     4
  2        3     2
  2        5     3
  3        4     4

我需要找到计数(托盘),计数(项目),总和(数量)

count(pallets) | count(items) | sum(qty)
----------------------------------------
      3                5           15

我可以得到总和(数量)和数量(项目)

select count(0) as totalItems, sum(qty) as total from table

有没有办法获得没有子查询的托盘数量？

Answer 1

是的,使用 DISTINCT

select count(distinct pallet) as pallets,
       sum(qty) as total, 
       count(0) as totalItems 
from your_table