使用 COUNT 来计算产品被订购的次数

use of COUNT to count the number of times the product has been ordered

我正在尝试使用 COUNT 来计算产品的订购次数。

以下是我所拥有的,但无法解决。我收到错误

SQL Error: ORA-00937: not a single-group group function

当我尝试使用按功能分组时,它说它不是按功能分组或无法使用。

CREATE OR REPLACE VIEW product_summary AS
    SELECT product_name, COUNT(*) AS order_count, item_total AS order_total
    FROM order_item_products

我认为错误很明显。添加 group by:

CREATE OR REPLACE VIEW product_summary AS
    SELECT product_name, COUNT(*) AS order_count,
           SUM(item_total) AS order_total
    FROM order_item_products
    GROUP BY product_name;