SQL获取列的总数或总和

Question

这是我当前拥有的查询。

`SELECT war.id, inv.pro_id, inv.quantity
FROM L4_Warehouses war, L4_Inventories inv, L4_Employees emp, L4_Orders ord
WHERE inv.war_id = war.id AND
      war.id = emp.war_id AND
      emp.id = ord.emp_id AND
      ord.status = 'P'
ORDER BY inv.war_id, inv.pro_id;`

此查询提供此表。

现在，我想要得到的最终结果是获得这些数量的总和，例如下面的示例

ID      PRO_ID      QUANTITY
1       100         18
1       101         6
1       110         6

Answer 1

尝试SUM和GROUP BY：

SELECT war.id, inv.pro_id, SUM(inv.quantity)
FROM L4_Warehouses war, L4_Inventories inv, L4_Employees emp, L4_Orders ord
WHERE inv.war_id = war.id AND
      war.id = emp.war_id AND
      emp.id = ord.emp_id AND
      ord.status = 'P'
GROUP BY war.id, inv.pro_id
ORDER BY inv.war_id, inv.pro_id;