C# C中的sql命令错误#

我编写这段代码是为了从数据库中的两个表中检索一些信息。但是当我运行它时，我得到了这个错误

列'eated_food.Cardserial'在选择列表中无效，因为它不包含在聚合函数或GROUP BY子句中

代码：

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如何解决它？

问题在于您的sql查询。如果使用

分组依据

，则无法选择未按分组或未聚合的列（例如，使用

Min/Max/Avg/Count

）

因此，您可以通过以下方式使其工作：例如，在此处更改您的旧查询：

SELECT eaten_food.cardserial, 
       eaten_food.date, 
       eaten_food.turn, 
       avb_food_count, 
       reserve_count 
FROM   reserve 
       INNER JOIN eaten_food 
               ON reserve.cardserial = eaten_food.cardserial 
GROUP  BY eaten_food.date 

致：

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SQL语句本身有问题。我会将其复制到SQL management studio并进行调试

group函数用于创建摘要行，因此select列需要是group by子句的一部分，或者是statmet的摘要类型，如sum（x）或count（x）

下面的方法可能有效

SELECT  Eaten_food.Cardserial ,
        Eaten_food.Date ,
        Count(Eaten_food.Turn) ,
        sum(Avb_food_count) ,
        sum(Reserve_count)
FROM    Reserve
        INNER JOIN Eaten_food ON Reserve.Cardserial = Eaten_food.Cardserial
GROUP BY Eaten_food.Date, Eaten_food.CardSerial

---

您希望查询的

分组依据

部分实现什么？

SELECT MIN(eaten_food.cardserial)AS Cardserial, 
       eaten_food.date, 
       MIN(eaten_food.turn) AS Turn, 
       SUM(avb_food_count) AS SumFoodCount, 
       SUM(reserve_count) AS SumReserveCount 
FROM   reserve 
       INNER JOIN eaten_food 
               ON reserve.cardserial = eaten_food.cardserial 
GROUP  BY eaten_food.date 

SELECT  Eaten_food.Cardserial ,
        Eaten_food.Date ,
        Count(Eaten_food.Turn) ,
        sum(Avb_food_count) ,
        sum(Reserve_count)
FROM    Reserve
        INNER JOIN Eaten_food ON Reserve.Cardserial = Eaten_food.Cardserial
GROUP BY Eaten_food.Date, Eaten_food.CardSerial