C# 如果我有每个员工的总分配假期列，如何计算假期余额？

我有一个列为分配的叶子的详细信息表。我有一个额外的列用于

LeavesTaken

。现在我想计算每个员工的假期余额，并相应地更新它

        {
            command.Connection = _connection;
            SqlDataReader reader = command.ExecuteReader();
            Employee employee = new Employee();
            List<Users.LeaveRequest> leaves = new List<Users.LeaveRequest>();
            while (reader.Read())
            {
                leaves.Add(new Users.LeaveRequest() { DayPart = reader.GetInt32(3), fromdate = reader["fromdate"].ToString(), todate = reader["todate"].ToString() });
            }
            reader.Close();
            if (leaves.Count>0)
            {
                leaveRequests = leaves;
            }
            else
            {
                leaveRequests = null;
            }

            command.CommandText = "SELECT TotalLeaves,LeavesTaken FROM empDetails WHERE empID = @empid";
            //command.Parameters.AddWithValue("@empid", CurrentUser.Employee.EmpID);
            reader = command.ExecuteReader();
            if (reader.Read())
            {
                employee.TotalLeaves = reader.GetInt32(0);
                employee.LeavesTaken = reader.GetDouble(1);
            }
            reader.Close();
            return employee;
        }````

{
command.Connection=\u Connection；
SqlDataReader=command.ExecuteReader（）；
员工=新员工（）；
列表叶子=新列表（）；
while（reader.Read（））
{
添加（新用户.LeaveRequest（）{DayPart=reader.GetInt32（3），fromdate=reader[“fromdate”].ToString（），todate=reader[“todate”].ToString（）；
}
reader.Close（）；
如果（叶数>0）
{
叶子=叶子；
}
其他的
{
leaveRequests=null；
}
command.CommandText=“从empDetails中选择TotalLeaves，LeavesTaken，其中empID=@empID”；
//command.Parameters.AddWithValue（“@empid”，CurrentUser.Employee.empid）；
reader=command.ExecuteReader（）；
if（reader.Read（））
{
employee.totaleaves=reader.GetInt32（0）；
employee.levestaken=reader.GetDouble（1）；
}
reader.Close（）；
返回员工；
}````

我可以想出三种解决方案，因为您没有准确地指定所需的内容，也没有指定示例数据：

您希望为员工计算总价值：

SELECT SUM(TotalLeaves), SUM(LeavesTaken)
FROM empDetails 
WHERE empID = @empid

您希望在这两个值之间保持平衡

SELECT SUM(TotalLeaves) - SUM(LeavesTaken)
FROM empDetails 
WHERE empID = @empid

如果每个

empID

有一条记录，您也可以尝试：

SELECT TotalLeaves - LeavesTaken
FROM empDetails 
WHERE empID = @empid

---

我很好奇为什么你的总假期是整数，但无论如何你可以在

CommandText

假设这三列

AlloctedLeaves、TotalLeaves、LeavesTaken的数据类型为
DECIMAL（4,2）

现在我想计算每个员工的假期余额，并相应地更新它

        {
            command.Connection = _connection;
            SqlDataReader reader = command.ExecuteReader();
            Employee employee = new Employee();
            List<Users.LeaveRequest> leaves = new List<Users.LeaveRequest>();
            while (reader.Read())
            {
                leaves.Add(new Users.LeaveRequest() { DayPart = reader.GetInt32(3), fromdate = reader["fromdate"].ToString(), todate = reader["todate"].ToString() });
            }
            reader.Close();
            if (leaves.Count>0)
            {
                leaveRequests = leaves;
            }
            else
            {
                leaveRequests = null;
            }

            command.CommandText = "SELECT TotalLeaves,LeavesTaken FROM empDetails WHERE empID = @empid";
            //command.Parameters.AddWithValue("@empid", CurrentUser.Employee.EmpID);
            reader = command.ExecuteReader();
            if (reader.Read())
            {
                employee.TotalLeaves = reader.GetInt32(0);
                employee.LeavesTaken = reader.GetDouble(1);
            }
            reader.Close();
            return employee;
        }````


更新
表empDetails

{
    command.CommandText = "UPDATE empDetails " + 
                          "SET TotalLeaves = TotalLeaves - llottedLeaves, " +
                          "LeavesTaken = LeavesTaken + AllottedLeaves, " +
                          "AllottedLeaves = 0" +
                          "WHERE AllottedLeaves <> 0 AND AllottedLeaves <= TotalLeaves";
    command.Connection = _connection;
    command.ExecuteNonQuery();
}

{
    command.CommandText = "UPDATE empDetails " + 
                          "SET TotalLeaves = TotalLeaves - llottedLeaves, " +
                          "LeavesTaken = LeavesTaken + AllottedLeaves, " +
                          "AllottedLeaves = 0" +
                          "WHERE empID = @empid";
    command.Parameters.AddWithValue("@empid", CurrentUser.Employee.EmpID);
    command.Connection = _connection;
    command.ExecuteNonQuery();
}


请发布示例数据库
LeaveBalance=TotalLeaves-LeavesTaken
。为什么要在表中更新它？您有一个AllocatedLeaves列和一个LeavesTaken列，因此您可以随时计算要在应用程序中显示的余额。请出示一些样本数据，并明确说明您需要什么。