Question

我正在尝试计算项目的总成本，并将该值放入名为cost的新列中。

在我的创建脚本中，值以字符为单位，但数据类型为money。

CREATE VIEW ordered_pizzas_view
AS 
    SELECT 
        orderpizza_id, order_id, ..., 
        CONCAT(range_price, ' ', crust_surcharge, ' ', sauce_surcharge) AS 'cost'
    FROM 
        order_pizza 
    INNER JOIN 
        ...
    WHERE 
        'cost' = (SELECT SUM(CAST(range_price AS MONEY)) FROM pizza_range) +
                 (SELECT SUM(CAST(crust_surcharge AS MONEY)) FROM crust) +
                 (SELECT SUM(CAST(Sauce_surcharge AS MONEY)) FROM sauce)

Answer 1

您对concat()的期望是什么？ concat()返回一个字符串值，该字符串值基于您的输入将是由空格分隔的三个货币值，例如$1.00 $2.00 $0.50

将其与金钱价值进行比较会产生错误。也许你只想添加值？

(range_price + crust_surcharge + sauce_surcharge ) as [cost]

注意：不要将字符串文字用作别名。

此外，您的where子句正在将字符串文字（'cost'）与组合子查询中的money数据类型进行比较。

where --'cost'
      (range_price + crust_surcharge + sauce_surcharge )
              = (select Sum(CAST(range_price as money)) from pizza_range) 
             + ( select Sum(CAST(crust_surcharge as money)) from crust ) 
             + ( select Sum(CAST(Sauce_surcharge as money)) from sauce )

注意：您不能在where子句中使用列别名，您必须重复表达式或引用子查询/派生表或其他运算符中的表达式。

SQL将varchar转换成金钱

1 个答案: