Question

我的员工薪资表包含：

public partial class S_EmployeeSalary
    {
        public int SalaryId { get; set; }
        public int TypeId { get; set; }
        public int UserId { get; set; }
        public double Salary { get; set; }
        public Nullable<double> ExtraSalary { get; set; }
        public Nullable<double> Insurance { get; set; }
        public Nullable<double> Sanctions { get; set; }
        public System.DateTime SalaryDate { get; set; }

        public virtual C_UserItems C_UserItems { get; set; }
    }

当用户点击它时我有一个按钮，它会自动创建上个月记录的副本，只更新创建的新月记录：

public ActionResult CreateNewRows(int typeId)
{
    IQueryable<S_EmployeeSalary> moduleItems = db.S_EmployeeSalary
        .Include(x => x.C_UserItems)
        .Where(x => x.TypeId == typeId && DbFunctions.DiffDays(x.SalaryDate, DateTime.Now) > 30 && DbFunctions.DiffDays(x.SalaryDate, DateTime.Now) < 30);

    foreach (var item in moduleItems)
    {
        S_EmployeeSalary entity = new S_EmployeeSalary
        {
            TypeId = typeId,
            UserId = item.UserId,
            Salary = item.Salary,
            ExtraSalary = item.ExtraSalary,
            Insurance = item.Insurance,
            Sanctions = item.Sanctions,
            SalaryDate = DateTime.Now
        };
        db.S_EmployeeSalary.Add(entity);
    }

    db.SaveChanges();
}

我的问题是我怎么能只指定上个月的记录才能选择它，我尝试了DbFunctions.DiffDays但它没有运作良好，有没有人能帮助我获得新想法？注意其员工的工资，所以我上个月不需要过去30天

Answer 1

取决于您是否需要上个月或过去30天（问题不清楚）

这是上个月：

var startOfTthisMonth = new DateTime(DateTime.Today.Year, DateTime.Today.Month, 1);       
var firstDay = startOfTthisMonth.AddMonths(-1);
var lastDay = startOfTthisMonth.AddDays(-1);

IQueryable<S_EmployeeSalary> moduleItems = db.S_EmployeeSalary
    .Include(x => x.C_UserItems)
    .Where(x => x.TypeId == typeId && 
                x.SalaryDate >= firstDay &&
                x.SalaryDate <= lastDay);

这是过去30天：

var firstDay = DateTime.Today.AddDays(-30);

IQueryable<S_EmployeeSalary> moduleItems = db.S_EmployeeSalary
    .Include(x => x.C_UserItems)
    .Where(x => x.TypeId == typeId && 
                x.SalaryDate >= firstDay);

Answer 2

看起来这部分不会返回结果，因为它不能同时变大和小于30。

DbFunctions.DiffDays(x.SalaryDate, DateTime.Now) > 30 && DbFunctions.DiffDays(x.SalaryDate, DateTime.Now) < 30)

实体框架选择上个月的记录

2 个答案: