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SELECT 单价,SUM(单价*数量) as 总和 FROM 用餐明细 GROUP BY 单价 WHERE 用餐单号=................
int i;
decimal a1;
a1 = 0;
while (SDR.Read())
{
a1 += decimal.Parse(SDR["计费单价"].ToString()) * int.Parse(SDR["计费数量"].ToString());
}
SDR.Close();
textBox5.text = a1.ToString();
using System;
using System.Collections.Generic;
using System.Data;
using System.Data.SqlClient;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApp1
{
class Program
{
static string dbConnectionString = "******************************"; // 你的数据库连接字符串
static void Main(string[] args)
{
// 获取数据表
string sql = "select * from 用餐明细 where 用餐单号=@用餐单号";
DataTable dataTable = ExecuteQuery(sql, new SqlParameter("@用餐单号", "A0002"));
// 计算总价格
double price = 0.0;
foreach (DataRow row in dataTable.Rows)
{
price += Convert.ToDouble(row["计费单价"].ToString()) * Convert.ToDouble(row["计费数量"].ToString());
}
// 打印输出
Console.WriteLine(price);
}
static DataTable ExecuteQuery(string sql, params SqlParameter[] parameters)
{
DataTable dataTable = new DataTable();
using (SqlDataAdapter adapter = new SqlDataAdapter(sql, dbConnectionString))
{
if (parameters != null && parameters.Length > 0)
{
adapter.SelectCommand.Parameters.AddRange(parameters);
}
adapter.Fill(dataTable);
}
return dataTable;
}
}
}