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Check if todays date exists in a table with Entity Framework

I have a database table with columns of type dateTime.
Now I need to see if there already is a row with today's date, but I don't know how to compare the column with the current date without the hour, minutes, seconds.
Basically I have 2022-02-04 14:06:21.080 and I need to check if there is a row created on 2022-02-04.
I'm looking for something like
if (db.dates.Where(x => x.SentDate == Date.Now).Count() > 0)
{
// Do something
}
else
{
// Do something else
}
I only need to see if it has a date from today it doesn't matter what time it was created.
Any help is much appreciated!

If you're filtering for a specific date you can use the DateTime.Date property on both DateTime objects. This will compare the date component of the DateTime:
db.dates.Where(x => x.SentDate.Date == DateTime.Now.Date)
// or
db.dates.Where(x => x.SentDate.Date == DateTime.Today)
If you have a nullable DateTime? column, then you use the Value property along with HasValue:
db.dates.Where(x => x.SentDate.HasValue
&& x.SentDate.Value.Date == DateTime.Today)
Unfortunately, expression trees do not support the null propagation operator ?. so we need to use the above method instead.
DateTime.Date can also be used for date ranges, but take care with the upper bound.
PS: DateTime.Today is the same as DateTime.Now.Date

You can check a date range
var today = DateTime.Today;
var tomorrow = today.AddDays(1);
if(db.dates.Where(x => x.SentDate >= today && x.SentDate < tomorrow) ...
The DateTime.Today Property gets the current date with the time component set to 00:00:00.

You can check a date range
var today = DateTime.Today;
var tomorrow = today.AddDays(1);
if(db.dates.Where(x => x.SentDate >= today && x.SentDate < tomorrow) ...
The DateTime.Today Property gets the current date with the time component set to 00:00:00.
Note that we test the lower bound with >= today (with today meaning today at 00:00:00) but the upper one with < tomorrow, since we do not want to include tomorrow at 00:00:00.

Another way is to convert the dates to string and compare.
if(db.dates.Any(m=>m.SentDate.ToString("d") == DateTime.Now.ToString("d"))){
//Do something else
}
else
{
// Do something else
}

If you use MS SQL Server you can use a special function EF.Functions.DateDiff that was created to be used with EF. It can count datetime difference from seconds to months. DateDiffDay is used to count days.
var dateTimeNow = DateTime.Now;
if (db.dates.Any(x => EF.Functions.DateDiffDay(x.SentDate , dateTimeNow) == 0 )
{
// ... there are today's dates
}
// ...

Optimizing date comparison query in Entity Framework

I am trying to optimize one of our most important queries and I would like to have some extra insights on how Entity Framework translates certain LINQ expressions.
I am using the repository pattern so my service layer (where I define my queries) is unaware of the actual data layer, which (currently) limits me to using only Where statements. Using joins and other constructs may help but that would require a rewrite of certain parts of the application. I'd like to exhaust all other options first before considering that.
I have come up with 3 variants of my query:
// Takes about 1900-2200ms for 120 records
public Expression<Func<Appointment, bool>> FilterByResources(DateTime startDate, DateTime endDate, IEnumerable<int> resourceIds)
{
// Appointments are filtered on the scheduler's start date, end date and the resources in the current page
Expression<Func<Appointment, bool>> filter = (x) => x.Assignments.Any(z => resourceIds.Contains(z.ResourceId))
&&
// Appointment starts somewhere between the start and end date
((DbFunctions.TruncateTime(x.StartDate).Value >= startDate && DbFunctions.TruncateTime(x.StartDate).Value <= endDate) ||
// Appointment started earlier than start date but ends earlier than end date
(DbFunctions.TruncateTime(x.EndDate).Value >= startDate && DbFunctions.TruncateTime(x.EndDate).Value <= endDate) ||
// Appointment starts and ends outside the boundaries
(DbFunctions.TruncateTime(x.StartDate).Value <= startDate && DbFunctions.TruncateTime(x.EndDate).Value >= endDate));
return filter;
}
Alternative #2:
// Takes about 2100ms for 120 records
public Expression<Func<Appointment, bool>> FilterByResources2(DateTime startDate, DateTime endDate, IEnumerable<int> resourceIds)
{
DateTime truncatedStartDate = startDate.Date;
DateTime truncatedEndDate = endDate.EndOfDay(); // Extension method that formats the time to 23:59:59
// Appointments are filtered on the scheduler's start date, end date and the resources in the current page
Expression<Func<Appointment, bool>> filter = (x) => x.Assignments.Any(z => resourceIds.Contains(z.ResourceId)) && (
(x.StartDate >= truncatedStartDate && x.StartDate <= truncatedEndDate) || // Appointment starts somewhere between the start and end date
(x.EndDate >= truncatedStartDate && x.EndDate <= truncatedEndDate) || // Appointment started earlier than start date but ends earlier than end date
(x.StartDate <= truncatedStartDate && x.EndDate >= truncatedEndDate) // Appointment starts and ends outside the boundaries
);
return filter;
}
Alternative 3:
// Takes about 1900ms for 120 records
public Expression<Func<Appointment, bool>> FilterByResources(DateTime startDate, DateTime endDate, IEnumerable<int> resourceIds)
{
DateTime truncatedStartDate = startDate.Date;
DateTime truncatedEndDate = endDate.EndOfDay(); // Extension method that formats the time to 23:59:59
// Appointments are filtered on the scheduler's start date, end date and the resources in the current page
Expression<Func<Appointment, bool>> filter = (x) => x.Assignments.Any(z => resourceIds.Contains(z.ResourceId)) && (
(x.StartDate.CompareTo(truncatedStartDate) >= 0 && x.StartDate.CompareTo(truncatedEndDate) <= 0) || // Appointment starts somewhere between the start and end date
(x.EndDate.CompareTo(truncatedStartDate) >= 0 && x.EndDate.CompareTo(truncatedEndDate) <= 0) || // Appointment started earlier than start date but ends earlier than end date
(x.StartDate.CompareTo(truncatedStartDate) <= 0 && x.EndDate.CompareTo(truncatedEndDate) >= 0) // Appointment starts and ends outside the boundaries
);
return filter;
}
A little explanation about this query: This query retrieves a list of appointments for a number of resources (i.e. people) between two dates. Because of that range, I need to include those records that start earlier, finish later or last longer than the range (hence the 3 expressions).
I tried switching the order of the expressions but the results remain stable. On average it takes between 1800ms and 2200ms for the entire web api call (I use postman for my tests)
So my question is how this query can be optimized? I think the date comparison expressions take the longest time but it may as well be the Any/Contains combination that slows down the query.

Daterange with startDate and endDate not working if both date same

I get the data returned of the selected date range which is between the range or isnt. but not if the startDate and endDate is the same. Like example: from 14.10.2017 - 14.10.2017. It returns me then no data (but it should because 5 database records are affected)
foreach (Content content in db.Contents)
{
if (content.ShippedDate < startDate || content.ShippedDate > endDate)
}
Anyone has a solution?

You should update the condition to include the same date.
1.1.2016 < 1.1.2016 //FALSE
1.1.2016 <= 1.1.2016 //TRUE
Adjusting conditions:
content.ShippedDate <= startDate
content.ShippedDate >= endDate
Code:
foreach (Content content in db.Contents)
{
if (content.ShippedDate <= startDate || content.ShippedDate >= endDate)
//the code here
}

use <= (smaller than or equal) and >= (greater than or equal) instead of < and >, this will match values that are equal as well rather than just the ones that are smaller or greater than given value.
Also please refer to this page to learn more about c# operators as this is a very basic questions
https://msdn.microsoft.com/en-us/library/6a71f45d.aspx

LINQ filter nullable datetime with matching params?

I need to filter my nullable datetime by day month and year.
I currently trying to do it by using string comparisons. I have this in where statement in linq:
DOB.ToString().StartsWith("2/25/19") || DOB == null
But its not working. I know its because the server doesnt store the date like that, but Im unsure as to how it is storing it, and how can I retrieve it and do the comparison.
I REALLY need this to happen on the database. I cant get everything and filter in the server.
I just want linq to filter dates by day, month, and year
Any help or pointers are appreciated.

You could try something like this (updated to include optional date components):
int? month = 2;
int? day = 25;
int? century = 19; // actual century minus one
// other LINQ here
.Where(x => x.DOB == null
|| ((month == null || x.DOB.Month = month)
&& (day == null || x.DOB.Day = day)
&& (century == null || x.DOB.Year / 100 == century)));

try this:
context.Entities.Where(e => e.Date != null && e.Date.Day == 15)
you can use DateTime.Day, DateTime.Month, DateTime.Year and the logical operators && and || to filter as you see fit. You must however check for nullity first or you may end up with NullExceptions

If you want to filter by day, month, year, use the example code below:
DateTime dateTime = DateTime.Now;
Console.WriteLine(dateTime.Day);
Console.WriteLine(dateTime.Month);
Console.WriteLine(dateTime.Year);
You can get those value from DateTime object. Then, you can apply filter on it.
After reading the comment, I got your point.
For example, you enter a string like this:
string search = "2/25/2015";
Now, you want to extract the value of the string to perform filter, right? Simply do:
string[] values = search.Split('/');
Then, the values would be [2, 25, 2015]. First element is month, second is day, third is year, that depends on how you define the format.

c# get all dates from database that appear with current week

trying to get all the dates from the db that are within the current week
i have email1DueDate, email2DueDate, email3DueDate
and i want to see if they are due to be sent within the current week

First you should calculate two DateTime values for the start of the week and the end of the week, you can do that like this (assuming Monday is the first day):
DateTime startOfWeek = DateTime.Today;
int delta = DayOfWeek.Monday - startOfWeek.DayOfWeek;
startOfWeek = startOfWeek.AddDays(delta);
DateTime endOfWeek = startOfWeek.AddDays(7);
next you can use this in your LINQ query to get the results you need, I am assuming you want results to be rows that have any of your due dates fall in the week:
var results = DB.Table.Where(x =>
(x.email1DueDate >= startOfWeek && x.email1DueDate < endOfWeek) ||
(x.email2DueDate >= startOfWeek && x.email2DueDate < endOfWeek) ||
(x.email3DueDate >= startOfWeek && x.email3DueDate < endOfWeek)
);
If this is not what you need then you will need to clarify your requirements

LINQ
listOfDates.Where(x => x.email1DueDate > beginOfWeekDate && x.email1DueDate < endOfWeekDate).ToList();
Of course you'll still have to figure out the begin and end dates