I would like to query the db for items with a date greater than or equal to a given date.
The date in the db is a datetime and records time.
If the user enters the search string "1/30/2014", they expect entries that occurred at any time on that date to be returned. However, anything that has a time after 12 am is not returned.
I know I could simply add a day to the search string, but is there a more appropriate way?
if (form["closedend"] != "")
{
DateTime d = DateTime.Parse(form["closedend"]);
traces = traces.Where(s => s.date_Closed >= d);
}
You can use the Date property to truncate the time part:
traces = traces.Where(s => s.date_Closed.Date <= d.Date);
On this way you'd include this day since both DateTimes are midnight.
Update if you use LINQ to Entities DateTime.Date is not supported, you could use this solution: Using DateTime in LINQ to Entities
.Where(s => EntityFunctions.TruncateTime(s.date_Closed) <= EntityFunctions.TruncateTime(d))
You said
with a date greater than or equal to a given date
but in your code you write
s.date_Closed <= d
I think you must change <= by >= to obtain dates greater or equal to d, now you're getting dates less or equal to d.
For this example you don't need neccessary any other dll. You can implement other function, which return bool, f.e:
public bool MyFunction(DateTime s)
{
DateTime d = DateTime.Parse(Your constructor);
return (s.date_Closed >= d);
}
var query = from obj in traces
where MyFunction(obj.date_Closed.Date)
select obj;
or:
var query = traces.Where(p => MyFunction(p.data_Closed.Date));
You can use DbFunctions.TruncateTime(StartDateTime) To remove the time from datetime.
if (form["closedend"] != "")
{
DateTime d = DateTime.Parse(form["closedend"]);
traces = traces.Where(s => DbFunctions.TruncateTime(s.date_Closed) >= DbFunctions.TruncateTime(d));
}
Related
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
}
// ...
I have a list of data that have datetimeoffset? as a column inside. I want to get specific data that has the month I want but don't know how. Below are those code I have tried.
This return me with error of No overload for method 'Tostring' which is weird since I can pass datetimeoffset? and use it in other function but if I do it directly inside where I get it, I can't use it.
int d = DateTime.Now.Month;
string f = d.ToString();
var s = _dbContext.Documents.FirstOrDefault(x => x.ApplyDate.ToString("MM") == f);
return Json(s);
This return null
int d = DateTime.Now.Month;
string f = d.ToString();
var s = _dbContext.Documents.FirstOrDefault(x => x.ApplyDate.Value.ToString("MM") == f);
return Json(s);
You can retrieve the month of a nullable datetimeoffset like this:
DateTimeOffset? dt;
dt?.Value.Month;
However, I really wonder if EF will be able to translate this:
x => x.ApplyDate?.Month == f
into a SQL expression. I presume that it will fallback to in-memory filtering.
Next to that, even if EF is able to translate this into a SQL expression, it won't be optimal as indexes that might be defined on that column will not be used.
Therefore, I'd suggest to rewrite your LINQ expression to something like this:
x :> x.ApplyDate != null && x.ApplyDate >= new DateTimeOffset(someDate.Year, someDate.Month, 1) && x.ApplyDate <= new DateTimeOffset(someDate.Year, someDate.Month, daysInMonth)
(Given you want to retrieve the data that belong to a specific month in a specific year. If you want to retrieve records that belong to a certain month, regardless the year, I see no other option)
DateTimeOffset? is Nullable type therefore is has no overload of ToString(string format) like DateTimeOffset has.
to get get the month value from your DateTimeOffset? you can
x.ApplyDate.Value.ToString("MM")
x.ApplyDate.Value.Month
please consider that you might want to check if ApplyDate.Value is null before obtaining its Month property
Your code above shows DateTime, not DateTimeOffSet.
DateTimeOffSet is Struct, and if you have a nullable value, you need to check the value first and then get the month from the value part
DateTimeOffSet myNullableDateTime = someValue...//
Option 1:
// notice I added value below
myNullableDateTime.HasValue? "?Month="+myNullableDateTime.EscapeDataString(myNullableDateTime.Value.ToString()):"")
Option 2:
if(myNullableDateTime.HasValue)
{
var Month = myNullableDateTime.Month
TimeSpan difference = DateTimeOffset.Now.Subtract(myNullableDateTime.Value);
// convert the difference to what you need and get Month
}
I have not compiled it, but it should get you the answer or pretty close.
I am using the method below to find a list of objects (from a sharepoint list) between a date range using a LINQ query. It is working fine but takes a lot of time, can it be optimized?
public System.Collections.Generic.List<ItineraryModel> FilterDashboard(string StartDate, string EndDate ,ClientContext clientContext, SharePointContext spContext)
{
var src = this.SpHelper.getAllListData(clientContext).ToList<ItineraryModel>();
System.Collections.Generic.List<ItineraryModel> source2 = src.Where(delegate (ItineraryModel x)
{
if (!(System.Convert.ToDateTime(x.StartDate).Date > System.Convert.ToDateTime(EndDate).Date))
{
return !(System.Convert.ToDateTime(x.EndDate).Date < System.Convert.ToDateTime(StartDate).Date);
}
return false;
}).ToList<ItineraryModel>();
return source2.Distinct<ItineraryModel>().ToList<ItineraryModel>();
}
If src has 1000 elements, how many times will you convert StartDate from string to a DateTime. Wouldn't it be more efficient if you would only do this once?
Furthermore, you return a List. Are you sure that all your callers will need the complete list? Could it be that some callers only want to know whether there are any elements? of maybe they want only the first element, or do first 24 elements to display on a screen. In other words: wouldn't it be more efficient to return an IEnumerable instead of a List.
If you create a LINQ like function, always consider to return an IEnumerable instead of a List, especially if you don't need the List to create your function.
Now you forgot to tell us the return value of GetAllListData.But let's assume that GetAllListData returns an IEnumerable sequence of ItenaryModels.
Apparently every ItenaryModel has at least a StartDate and an EndDate. You don't want all ItenaryModels, you only want those ItenaryModels that started in the interval of input parameters startDate and endDate, or in other words where property StartDate >= input parameter startDate and property EndDate <= input parameter endDate.
IEnumerable<ItenaryModel> FilterDashboard(string textStartDate, string textEndDate, ...)
{
// TODO: check for non-null textStartDate, textEndDate
// convert the input dates to DateTime:
DateTime startDate = DateTime.Parse(textStartDate);
DateTime endDate = Datetime.Parse(textEndDate);
// TODO: decide what to do if dates can't be parsed
// TODO: decide what to do if startDate > endDate?
IEnumerable<ItenaryModel> itenaryModels = this.SpHelper.getAllListData(clientContext);
// the easiest is a foreach, alternatively use a LINQ where.
foreach (var itenaryModel in itenaryModels)
{
DateTime itenaryStartDate = DateTime.Parse(itenaryModel.StartDate.Date);
DateTime itenaryEndDate = DateTime.Parse(itenaryMode.EndDate.Date);
// TODO: decide what to do if can't be parsed
if (startDate <= itenaryStartDate && itenaryEndDate <= endDate)
{
// put this itenaryModel in the returned enumeration
yield return itenaryModel;
}
}
}
Alternatively you could use a LINQ where. This is not faster!
DateTime startDate = DateTime.Parse(textStartDate);
DateTime endDate = Datetime.Parse(textEndDate);
IEnumerable<ItenaryModel> itenaryModels = this.SpHelper.getAllListData(clientContext);
return itenaryModels.Where(itenaryModel =>
startDate <= DateTime.Parse(itenaryModel.StartDate.Date) &&
DateTime.Parse(itenaryModel.EndDate.Date) <= endDate);
You are loading the list items into the memory as a whole, then search for it. #Harald Coppoolse has given all possible answers about LINQ.
As an alternative approach, you can utilize CAML queries for that. You are using SPHelper whose internals are alien to me. But you can use old school SharePoint CAML queries for performance.
I have data in my database that contains the following filed.
Id | name | RegDate
1 John 2014-09-05
2 mike 2014-09-05
3 Duke 2014-10-14
I'm performing a query to count the number of values where the reg date is equal 09. 09 is the month of the date.
I'm trying to convert the date I store in db in a month format then get a new month of a system date to get the result.
Here is my query in linq but it keeps on giving the wrong count. please I need your help. thanks.
var CountPassengers = (from c in db.CountPassengerManifestViews where c.DepartureDate.Month.ToString()== DateTime.Now.AddMonths(-1).ToString("MM") select c).Count();
I would strongly recommend that you get rid of all the string manipulation. Your query doesn't conceptually have anything to do with strings, so why are you introducing them into the code?
You can write your query as:
int currentMonth = DateTime.Today.AddMonths(-1).Month;
var passengerCount = db.CountPassengerManifestViews
.Count(c => c.DepartureDate.Month == currentMonth);
However, that will only filter by month - it won't filter by month and year, so if you have data from 2013 that would be included too. It's more likely that you want something like:
DateTime oneMonthAgo = DateTime.Today.AddMonths(-1);
DateTime start = oneMonthAgo.AddDays(1 - oneMonthAgo.Day);
DateTime end = start.AddMonths(1);
var passengerCount = db.CountPassengerManifestViews
.Count(c => c.DepartureDate >= start &&
c.DepartureDate < end);
That way you're expressing a range of dates, rather than just extracting the month part.
where c.DepartureDate.Month == DateTime.Now.AddMonths(-1).Month
You don't compare string representation, because it's already converted into DateTime object, so it doesn't make sense to do it your way. This simple change should be enough.
I am not sure why you are doing the string manipulation but if you only want to compare the month part of the two dates then do the following:
where c.DepartureDate.Month== DateTime.Now.AddMonths(-1).Month
I think your code compares Month.ToString() that gives "9" with ToString("MM") that gives "09".
You could also improve by removing ".ToString()":
int lastMonth = DateTime.Now.AddMonths(-1).Month;
var CountPassengers = (from c in db.CountPassengerManifestViews where c.DepartureDate.Month == lastMonth select c).Count();
Regards
Try this
var CountPassengers = (from c in db.CountPassengerManifestViews
where c.DepartureDate.Month.ToString("MM")== DateTime.Now.AddMonths(-1).ToString("MM")
select c).Count();
var month = DateTime.Now.AddMonths(-1).Month;
var CountPassengers = db.CountPassengerManifestViews.Count(c => c.DepartureDate.Month == month);
Is there a way to compare two DateTime variables in Linq2Sql but to disregard the Time part.
The app stores items in the DB and adds a published date. I want to keep the exact time but still be able to pull by the date itself.
I want to compare 12/3/89 12:43:34 and 12/3/89 11:22:12 and have it disregard the actual time of day so both of these are considered the same.
I guess I can set all the times of day to 00:00:00 before I compare but I actually do want to know the time of day I just also want to be able to compare by date only.
I found some code that has the same issue and they compare the year, month and day separately. Is there a better way to do this?
try using the Date property on the DateTime Object...
if(dtOne.Date == dtTwo.Date)
....
For a true comparison, you can use:
dateTime1.Date.CompareTo(dateTime2.Date);
This is how I do this in order to work with LINQ.
DateTime date_time_to_compare = DateTime.Now;
//Compare only date parts
context.YourObject.FirstOrDefault(r =>
EntityFunctions.TruncateTime(r.date) == EntityFunctions.TruncateTime(date_to_compare));
If you only use dtOne.Date == dtTwo.Date it wont work with LINQ (Error: The specified type member 'Date' is not supported in LINQ to Entities)
If you're using Entity Framework < v6.0, then use EntityFunctions.TruncateTime
If you're using Entity Framework >= v6.0, then use DbFunctions.TruncateTime
Use either (based on your EF version) around any DateTime class property you want to use inside your Linq query
Example
var list = db.Cars.Where(c=> DbFunctions.TruncateTime(c.CreatedDate)
>= DbFunctions.TruncateTime(DateTime.UtcNow));
DateTime dt1 = DateTime.Now.Date;
DateTime dt2 = Convert.ToDateTime(TextBox4.Text.Trim()).Date;
if (dt1 >= dt2)
{
MessageBox.Show("Valid Date");
}
else
{
MessageBox.Show("Invalid Date... Please Give Correct Date....");
}
DateTime? NextChoiceDate = new DateTime();
DateTIme? NextSwitchDate = new DateTime();
if(NextChoiceDate.Value.Date == NextSwitchDate.Value.Date)
{
Console.WriteLine("Equal");
}
You can use this if you are using nullable DateFields.
DateTime dt1=DateTime.ParseExact(date1,"dd-MM-yyyy",null);
DateTime dt2=DateTime.ParseExact(date2,"dd-MM-yyyy",null);
int cmp=dt1.CompareTo(dt2);
if(cmp>0) {
// date1 is greater means date1 is comes after date2
} else if(cmp<0) {
// date2 is greater means date1 is comes after date1
} else {
// date1 is same as date2
}
DateTime econvertedDate = Convert.ToDateTime(end_date);
DateTime sconvertedDate = Convert.ToDateTime(start_date);
TimeSpan age = econvertedDate.Subtract(sconvertedDate);
Int32 diff = Convert.ToInt32(age.TotalDays);
The diff value represents the number of days for the age. If the value is negative the start date falls after the end date. This is a good check.
In .NET 5:
To compare date without time you must use EF.Functions.DateDiffDay() otherwise you will be comparing in code and this means you are probably pulling way more data from the DB than you need to.
.Where(x => EF.Functions.DateDiffDay(x.ReceiptDate, value) == 0);
You can try
if(dtOne.Year == dtTwo.Year && dtOne.Month == dtTwo.Month && dtOne.Day == dtTwo.Day)
....
In your join or where clause, use the Date property of the column. Behind the scenes, this executes a CONVERT(DATE, <expression>) operation. This should allow you to compare dates without the time.
int o1 = date1.IndexOf("-");
int o2 = date1.IndexOf("-",o1 + 1);
string str11 = date1.Substring(0,o1);
string str12 = date1.Substring(o1 + 1, o2 - o1 - 1);
string str13 = date1.Substring(o2 + 1);
int o21 = date2.IndexOf("-");
int o22 = date2.IndexOf("-", o1 + 1);
string str21 = date2.Substring(0, o1);
string str22 = date2.Substring(o1 + 1, o2 - o1 - 1);
string str23 = date2.Substring(o2 + 1);
if (Convert.ToInt32(str11) > Convert.ToInt32(str21))
{
}
else if (Convert.ToInt32(str12) > Convert.ToInt32(str22))
{
}
else if (Convert.ToInt32(str12) == Convert.ToInt32(str22) && Convert.ToInt32(str13) > Convert.ToInt32(str23))
{
}