如何编写一个 Linq 查询来返回特定日期期间的行？

Question

我正在使用 EF core 7 和 C#

在模型中，一名员工有多个期间和许多票证。

我有以下课程：

public class Employee
{    
    public string EmployeeId { get; set; }    
    
    public string FullName { get; set; }

    public List<Period> Periods { get; set; }
    
    public List<Ticket> Tickets { get; set; }

}

public class Period
{
    public int PeriodId { get; set; }  
    
    public DateTime From { get; set; }
    
    public DateTime To { get; set; }
    
    public Employee Employee { get; set; }
    
    public string EmployeeId { get; set; } //FK pointing to Employee
}

public class Ticket
{ 
    public string TicketId { get; set; }        
    
    public DateTime CreationDate { get; set; }
   
    public string EmployeeId { get; set; } //FK pointing to Employee
}

如何编写一个 linq 查询来返回其中的票证 员工的期限范围？，我需要的结果为

IQueryable<Ticket>

。

这是我正在尝试的查询：

//I create a list of employees Id's
var employeeIds= new List<string> {"9854","4587","2587"}

 IQueryable<Ticket> result =
     from ticket in DbContext.Tickets
     where employeeIds.Contains(ticket.EmployeeId) &&
     
     //Here I need to set the condition for tickets
     // that are inside the Period of each employee
     
    //[Period.From , Period.To] 
     
     select ticket;

Answer 1

这应该就是你想要的：

 IQueryable<Ticket> result = 
     from ticket in Tickets
     join employee in Employee on ticket.EmployeeId equals employee.EmployeeId
     where employeeIds.Contains(employee.EmployeeId) 
        && Periods.Any(p => p.EmployeeId == employee.EmployeeId 
            && ticket.CreationDate >= p.From && ticket.CreationDate <= p.To)
    select ticket;