出现“标量子查询产生多个元素”错误

Question

SELECT
  CONCAT(warehouse.warehouse_id,warehouse.warehouse_alias) AS warehouse_name,
  (SELECT
  COUNT(*)
    FROM focused-mote-392209.warehouse_orders.orders AS orders
    GROUP BY
    orders.warehouse_id
  ) AS total_orders,
FROM
  focused-mote-392209.warehouse_orders.warehouse AS warehouse
INNER JOIN
  focused-mote-392209.warehouse_orders.orders AS orders 
  ON warehouse.warehouse_id = orders.warehouse_id
GROUP BY
warehouse_name

我想按仓库对订单进行分组，但是当我运行此查询时，我收到“标量子查询生成多个元素”错误。我该如何解决这个问题？

我尝试在查询结束时对订单进行分组，但当时我无法对我想要选择的内容进行分组，例如“warehouse_id”和“warehouse_alias”，所以我尝试使用 concat。

Answer 1

试试这个：

SELECT
  CONCAT(warehouse.warehouse_id,warehouse.warehouse_alias) AS warehouse_name,
  COUNT(orders.warehouse_i) AS total_orders
FROM
  focused-mote-392209.warehouse_orders.warehouse AS warehouse
INNER JOIN
  focused-mote-392209.warehouse_orders.orders AS orders 
  ON warehouse.warehouse_id = orders.warehouse_id
GROUP BY
warehouse_name