我编写了这段代码来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'Eaten_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:
private void button8_Click(object sender, EventArgs e)
{
using (SqlConnection con = new SqlConnection(WF_AbsPres_Food.Properties.Settings.Default.DbConnectionString))
{
con.Open();
SqlDataAdapter a = new SqlDataAdapter("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", con);
SqlCommandBuilder comdBuilder = new SqlCommandBuilder(a);
DataTable t = new DataTable();
//t.Locale = System.Globalization.CultureInfo.InvariantCulture;
a.Fill(t);
bindingSource3.DataSource = t;
/// bind the grid view with binding source
Reserve_dataGridView.AutoResizeColumns(DataGridViewAutoSizeColumnsMode.AllCellsExceptHeader);
Reserve_dataGridView.ReadOnly = true;
Reserve_dataGridView.DataSource = bindingSource3;
Reserve_dataGridView.DataSource = t;
con.Close();
}
}
我该如何解决?
答案 0 :(得分:7)
问题是你的SQL查询。如果您使用Group By
,则无法选择未分组或未汇总的列(例如,使用Min/Max/Avg/Count
)。
所以你可以通过这种方式让它工作,在这里改变你的旧查询:
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
为:
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
答案 1 :(得分:1)
您的SQL语句本身有问题。我将它复制到SQL管理工作室并进行调试。
组函数用于创建汇总行,因此您的选择列要么必须是group by子句的一部分,要么是sum(x)或count(x)
之类的statmet的汇总类型以下可能有用..
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