I'm trying to counting how many messages sent per hour. but my code returns wrong result
This is original sqlite query that I used, it works right.
SELECT Hours.hour, ifnull(count(Messages.hour),0) as count Hours LEFT JOIN Messages on Messages.hour = Hours.hour by Hours.hour
but I'm a new at LINQ and here is my code and query.
int[] Hours = { 0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23 };
var sortByHour = from h in Hours
join m in Messages on h equals m.Hour into g
orderby h ascending
select new
{
Hour = h,
Total = g.Count()
};
and it returns
[0] { Hour = 0, Total = 33485 }
[1] { Hour = 1, Total = 0 }
[2] { Hour = 2, Total = 0 }
[3] { Hour = 3, Total = 0 }
...
[23] { Hour = 23, Total = 0 }
first data has number of total rows and others has 0. its wrong.
result should have to be like this
[0] { Hour = 0, Total = 501 }
[1] { Hour = 1, Total = 408 }
[2] { Hour = 2, Total = 181 }
[3] { Hour = 3, Total = 84 }
...
[23] { Hour = 23, Total = 1055 }
how can I fix my code? thanks in advanced.
Answer is
var res = from h in Hours
join m in Messages on h equals m.Hour into jn
from j in jn.DefaultIfEmpty()
select new
{
hour = h,
count = j != null ? jn.Count(i => i.Hour == h) : 0
}
But if you have Database, model, relation between Hours and Messages, and we are talking about linq to sql or lint to entities, it's better use (as usr mentioned at comments) h.Messages.Count() and let Database engine make a request
Something like this should solve your problem.
Setup:
int[] Hours = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23 };
var Messages = new List<Message>()
{
new Message() { MessageId = 1, Hour = 5 },
new Message() { MessageId = 2, Hour = 7 },
new Message() { MessageId = 3, Hour = 5 },
new Message() { MessageId = 4, Hour = 3 },
new Message() { MessageId = 5, Hour = 7 },
new Message() { MessageId = 6, Hour = 5 },
};
Query:
var sortByHour = Hours.Select(h =>
new { Hour = h, Total = Messages.Count(m => m.Hour == h) } );
Basically, you just select each hour and its count in Messages.
Related
I am keeping staff clock-in times daily.
Sometimes they work the next day without taking any break.
WHAT I NEED IS
Without a break,the Total Hrs of staff who finish at midnight.
For example
Staff
Start
End
Staff A
9 AM
3 PM
Staff A
3 PM
10 PM
Staff A
10 PM
12:00 AM
Staff B
3 AM
9 PM
Staff B
10 PM
12:00 AM
Staff C
3 AM
9 PM
Staff D
10 PM
12:00 AM
In the above table, both staffs finished at midnight.
Staff A worked 15hrs without any breaks.
But Staff B had a break between 9 PM and 10 Pm.
Expected result:
Staff
Total
Staff A
15
Staff B
2
Staff C
0 because he didn't finish at midnight.
Staff C
2
I tried for loop, but it failed because each staff has a different number of entries, codes got messy at the end.
I tried LINQ and joining the same table etc. but couldn't figure it out.
This website is my last option.
Thanks advance for help.
Okay, this answer will need a bunch more work if you need this for work segments that cross dates or multiple dates. This assumes all work segments are in the same day.
The following groups all segments by staff, then adds up each segment total minutes. Then only returns the total if the last segment ends at midnight.
This test code returns the following:
Staff A: 15
Staff B: 20
Staff C: 0
Staff D: 2
Here's the code:
void Main()
{
var segments = GetTestData();
DateTime midnight = DateTime.Now.AddDays(1).Date;
var results = segments
.GroupBy(s => s.Name)
.Select(grp =>
new {
Name = grp.Key,
Total = grp.Max(g => g.EndDate) == midnight
? grp.Sum(g => g.EndDate.Subtract(g.StartDate).TotalMinutes)
: 0
});
foreach (var result in results)
{
Console.WriteLine($"{result.Name}: {result.Total/60F:#,##0}");
}
}
class Segment
{
public string Name { get; set; }
public DateTime StartDate { get; set; }
public DateTime EndDate { get; set; }
}
Segment[] GetTestData()
{
return new[]
{
new Segment { Name = "Staff A", StartDate = new DateTime(2023, 1, 18, 9 , 0, 0), EndDate = new DateTime(2023, 1, 18, 15, 0, 0) },
new Segment { Name = "Staff A", StartDate = new DateTime(2023, 1, 18, 15, 0, 0), EndDate = new DateTime(2023, 1, 18, 22, 0, 0) },
new Segment { Name = "Staff A", StartDate = new DateTime(2023, 1, 18, 22, 0, 0), EndDate = new DateTime(2023, 1, 19, 0 , 0, 0) },
new Segment { Name = "Staff B", StartDate = new DateTime(2023, 1, 18, 3 , 0, 0), EndDate = new DateTime(2023, 1, 18, 21, 0, 0) },
new Segment { Name = "Staff B", StartDate = new DateTime(2023, 1, 18, 22, 0, 0), EndDate = new DateTime(2023, 1, 19, 0 , 0, 0) },
new Segment { Name = "Staff C", StartDate = new DateTime(2023, 1, 18, 3 , 0, 0), EndDate = new DateTime(2023, 1, 18, 21, 0, 0) },
new Segment { Name = "Staff D", StartDate = new DateTime(2023, 1, 18, 22, 0, 0), EndDate = new DateTime(2023, 1, 19, 0 , 0, 0) }
};
}
I have several classes of business logic:
public class Client {
public string Code { get; set; } = string.Empty;
public string Status { get; set; } = string.Empty;
public string Account { get; set; } = string.Empty;
public Total Total { get; set; } = new Total();
public List<Month> Months { get; set; } = new List<Month>();
}
public class Month {
public int Number { get; set; } = 0;
public string Name { get; set; } = string.Empty;
public DateTime Start { get; set; } = new DateTime();
public DateTime End { get; set; } = new DateTime();
public Total Summary { get; set; } = new Total();
}
public class Total {
public int Count { get; set; } = 0;
public decimal Sum { get; set; } = 0.0m;
}
which are instanced as follows:
List<Client> clients = new List<Client>() {
new Client {
Code = "7002.70020604",
Status = "Active",
Account = "7002.915940702810005800001093",
Total = new Total {
Count = 9,
Sum = 172536.45m
},
Months = new List<Month>() {
new Month {
Number = 0,
Name = "January",
Start = new DateTime(2021, 1, 1, 0, 0, 0),
End = new DateTime(2021, 1, 31, 23, 59, 59),
Summary = new Total {
Count = 6,
Sum = 17494.50m
}
},
new Month {
Number = 1,
Name = "February",
Start = new DateTime(2021, 2, 1, 0, 0, 0),
End = new DateTime(2021, 2, 28, 23, 59, 59),
Summary = new Total {
Count = 3,
Sum = 155041.95m
}
},
new Month {
Number = 2,
Name = "March",
Start = new DateTime(2021, 3, 1, 0, 0, 0),
End = new DateTime(2021, 3, 31, 23, 59, 59),
Summary = new Total {
Count = 0,
Sum = 0.0m
}
}
}
},
new Client {
Code = "7002.70020604",
Status = "Active",
Account = "7002.800540702810205800001093",
Total = new Total {
Count = 4,
Sum = 16711.21m
},
Months = new List<Month>() {
new Month {
Number = 0,
Name = "January",
Start = new DateTime(2021, 1, 1, 0, 0, 0),
End = new DateTime(2021, 1, 31, 23, 59, 59),
Summary = new Total {
Count = 0,
Sum = 0.0m
}
},
new Month {
Number = 1,
Name = "February",
Start = new DateTime(2021, 2, 1, 0, 0, 0),
End = new DateTime(2021, 2, 28, 23, 59, 59),
Summary = new Total {
Count = 0,
Sum = 0.0m
}
},
new Month {
Number = 2,
Name = "March",
Start = new DateTime(2021, 3, 1, 0, 0, 0),
End = new DateTime(2021, 3, 31, 23, 59, 59),
Summary = new Total {
Count = 4,
Sum = 16711.21m
}
}
}
}
};
I'm trying to arrange aggregate data of a view like this:
+---------------+--------+------------------+-------------------+------------------+-------------------+
| Code | Status | January | February | March | Total |
| | +-------+----------+-------+-----------+-------+----------+-------+-----------+
| | | Count | Sum | Count | Sum | Count | Sum | Count | Sum |
+---------------+--------+-------+----------+-------+-----------+-------+----------+-------+-----------+
| 7002.70020604 | Active | 6 | 17494.50 | 3 | 155041.95 | 4 | 16711.21 | 13 | 189247.66 |
+---------------+--------+-------+----------+-------+-----------+-------+----------+-------+-----------+
using projection like this:
clients
.GroupBy(x => x.Code)
.Select(y => new {
Code = y.First().Code,
Status = y.First().Status,
Account = y.First().Account,
Total = new {
Count = y.Sum(z => z.Total.Count),
Sum = y.Sum(z => z.Total.Sum)
},
Months = new {
/*
?
*/
}
});
But I can't project the data by month. Assuming the date range (months) can be more than just this example. Please help!
Full interactive code listing at dotnetfiddle
You can use SelectMany to get months out of y and then group by month similarly as you group by code:
//...
Months = y
.SelectMany(client => client.Months)
.GroupBy(month => month.Name, (_, months) => new {
Number = months.First().Number,
Name = months.First().Name,
Start = months.First().Start,
End = months.First().End,
Summary = new {
Count = months.Sum(z => z.Summary.Count),
Sum = months.Sum(z => z.Summary.Sum)
}
}).ToList()
//...
That being said I don't suggest to use y.First() or months.First() more than once in each function because it makes an enumeration each time it is used. The following should in general have better performance:
(_, months) => {
var month = months.First();
return new {
Number = month.Number,
Name = month.Name,
Start = month.Start,
End = month.End,
Summary = new {
Count = months.Sum(z => z.Summary.Count),
Sum = months.Sum(z => z.Summary.Sum)
}
}
}
which is also not ideal because we're still making 3 enumerations here (1 enumeration in .First() and 1 enumeration for every .Sum(...)).
Even better approach would be to use Aggregate function which will do only a single enumeration:
(_, months) => months
.Aggregate((res, nextVal) => new Month {
Number = nextVal.Number,
Name = nextVal.Name,
Start = nextVal.Start,
End = nextVal.End,
Summary = new Total {
Count = res.Summary.Count + nextVal.Summary.Count,
Sum = res.Summary.Sum + nextVal.Summary.Sum
}
})
This LINQ query should prepare data for visualization:
clients
.GroupBy(x => new {x.Code, x.Status})
.Select(g => new
{
Code = g.Key
MonthsSummary = g.SelectMany(x => x.Months)
.OrderBy(x => x.Start)
.GroupBy(x => new {x.Start, x.Name})
.Select(gm => new
{
gm.Key.Name,
Count = gm.Sum(x => x.Summary.Count),
Sum = gm.Sum(x => x.Summary.Sum),
})
.ToList()
});
Good morning. I am writing a unit test to validate that my API handler is sorting the collection properly. As you can see, it's mocked data and I intentionally created the test data out of order to test the OrderBy functionality. Once the handler returns the DTO collection, I want to validate that the "act" collection is in the same order as my "expectedDTO" collection. Here's the code:
[TestMethod]
public async Task GetByDay_ReturnsDtoList_WhenFound()
{
var testData = TestMethodData();
var expectedCalendarDto = ExpectedDto();
var testCalendar = testData;
var query = new GetCalendarByDaysQuery();
_mockCalendarRepo.Setup(m => m.GetItemsAsync(It.IsAny<ISpecification<CalendarDay>>(), null, null))
.ReturnsAsync(testCalendar);
var sut = new GetCalendarByDaysHandler(_mockCalendarRepo.Object, _mapper);
var act = await sut.HandleAsync(query);
Assert.IsNotNull(act);
Assert.IsInstanceOfType(act, typeof(IEnumerable<CalendarDto>));
Assert.AreEqual(expectedCalendarDto, act);
}
private GetItemsResult<IEnumerable<CalendarDay>> TestMethodData()
{
var testData = new GetItemsResult<IEnumerable<CalendarDay>>();
testData.ContinuationToken = null;
testData.Results = new List<CalendarDay>()
{
new CalendarDay { Id = "4-5-4|2021-04-01", FiscalYear = 2021, CalendarType = "4-5-4", Quarter = 2, Period = 4, CalendarDate = "2021-04-01", WeekOfYear = 13, DayOfYear = 61, WeekOfPeriod = 1 },
new CalendarDay { Id = "4-5-4|2021-08-01", FiscalYear = 2021, CalendarType = "4-5-4", Quarter = 3, Period = 8, CalendarDate = "2021-08-01", WeekOfYear = 24, DayOfYear = 121, WeekOfPeriod = 1 },
new CalendarDay { Id = "4-5-4|2021-01-01", FiscalYear = 2021, CalendarType = "4-5-4", Quarter = 1, Period = 1, CalendarDate = "2021-01-01", WeekOfYear = 1, DayOfYear = 1, WeekOfPeriod = 1 }
};
return testData;
}
private IEnumerable<CalendarDto> ExpectedDto()
{
var testDto = new List<CalendarDto>()
{
new CalendarDto { FiscalYear = 2021, CalendarType = "4-5-4", Quarter = 1, Period = 1, CalendarDate = "2021-01-01", WeekOfYear = 1, DayOfYear = 1, WeekOfPeriod = 1 },
new CalendarDto { FiscalYear = 2021, CalendarType = "4-5-4", Quarter = 2, Period = 4, CalendarDate = "2021-04-01", WeekOfYear = 13, DayOfYear = 61, WeekOfPeriod = 1 },
new CalendarDto { FiscalYear = 2021, CalendarType = "4-5-4", Quarter = 3, Period = 8, CalendarDate = "2021-08-01", WeekOfYear = 24, DayOfYear = 121, WeekOfPeriod = 1 }
};
return testDto;
}
Currently, in trying to compare the two collections, the test is failing saying that they aren't equal.
Assert.AreEqual failed. Expected:<System.Collections.Generic.List`1[cscentcalendar.infrastructure.DTOs.CalendarDto]>. Actual:<System.Collections.Generic.List`1[cscentcalendar.infrastructure.DTOs.CalendarDto]>.
Not sure what I'm doing wrong. Any assistance would be greatly appreciated.
I believe I solved the problem by using fluent assertion and adding the following line of code to test the two collections. Let me know if this is incorrect. Thanks again!
expectedCalendarDto.Should().BeEquivalentTo(act);
I want to fetch values from database with specific intervals in C# and need a single query for that.
This is how my Database looks like
Id SensorId Value CreatedOn
------------------------------------------------
1 8 33.5 15-11-2012 5:48 PM
2 5 49.2 15-11-2012 5:48 PM
3 8 33.2 15-11-2012 5:49 PM
4 5 48.5 15-11-2012 5:49 PM
5 8 31.8 15-11-2012 5:50 PM
6 5 42.5 15-11-2012 5:50 PM
7 8 36.5 15-11-2012 5:51 PM
8 5 46.5 15-11-2012 5:51 PM
9 8 39.2 15-11-2012 5:52 PM
10 5 44.4 15-11-2012 5:52 PM
11 8 36.5 15-11-2012 5:53 PM
12 5 46.5 15-11-2012 5:53 PM
13 8 39.2 15-11-2012 5:54 PM
14 5 44.4 15-11-2012 5:54 PM
.. .. ..... ...................
The interval is in minutes.
So, if the interval is 10 minutes, then we need the values at 5:48, 5:58, 6:08 and so on...
I tried doing it with a while loop but it is taking a lot of time as i shoot multiple queries to the database.
Is there any way of getting the data in a single query?
You can use datepart along with a modulus to get the matching rows (eg, #interval = 10, #offset = 8):
SELECT * FROM table
WHERE datepart(minute, CreatedOn) % #interval = #offset
Edit
Note that the above isn't a general solution of selecting by intervals. It will work across hours (and therefore across days) for intervals like 2, 3, 4, 5 ... any minute interval which divides into 60.
If you want to use a strange interval like 7 minutes, then you'd have to define a starting time for the interval and calculate the total minutes for each row, inclusive of hours/days. At that point you'd be best to create an indexed, computed column on the table, based on a user-defined function that calculates the interval in question.
Here is how you can do it, explanation is contained within comments in code:
/*We want 10-minute intervals starting
from minimum date to next day same time*/
DECLARE #startDateTime DATETIME = (
SELECT MIN(CreatedOn)
FROM #yourTable
)
DECLARE #endDateTime DATETIME = DATEADD(DAY, 1, #startDateTime)
DECLARE #startDateTimeTable TABLE (dt DATETIME)
INSERT #startDateTimeTable VALUES (#startDateTime)
/*Create a table that contains relevant datetimes (10-minute
intervals from starting date to end date)*/
;WITH a AS (
SELECT dt
FROM #startDateTimeTable
UNION ALL
SELECT DATEADD(MINUTE, 10, a.dt)
FROM a
JOIN #startDateTimeTable b ON a.dt <= #endDateTime
)
SELECT *
INTO #requiredDateTimes
FROM a
OPTION (MAXRECURSION 32767)
/*Now join data table to datetime table to
filter out only records with datetimes that we want*/
SELECT *
FROM #yourTable a
JOIN #requiredDateTimes b ON
a.CreatedOn = b.dt
Here is an SQL Fiddle
Any of the answers that recommend using modulus (%) are making several assumptions:
You will always have a reading on every sensor at the exact minute in question
You will never have more than one reading in a minute per sensor.
You will never have to deal with intervals smaller than a minute.
These are probably false assumptions, so you need a different approach. First, make a map of all of the time points you are querying over. Then take the last reading from each sensor on or before that point.
Here's a full unit test showing how it can be done in pure linq-to-objects. You may need some minor changes to the query to get it to work in linq-to-sql, but this is the right approach. I used the exact sample data you provided.
As an aside - I hope you are recording your CreatedOn dates in UTC, or you will have ambiguity of sensor readings during daylight savings time "fall-back" transitions. You need to record as DateTime in UTC, or using DateTimeOffset. Either are an appropriate representation of instantaneous time. A DateTime with .Kind of Local or Unspecified is only a valid representation of calendar time, which is not appropriate for sensor readings.
[TestClass]
public class LinqIntervalQueryTest
{
public class Item
{
public int Id { get; set; }
public int SensorId { get; set; }
public double Value { get; set; }
public DateTime CreatedOn { get; set; }
}
[TestMethod]
public void Test()
{
var data = new[]
{
new Item { Id = 1, SensorId = 8, Value = 33.5, CreatedOn = new DateTime(2012, 11, 15, 17, 48, 0, DateTimeKind.Utc) },
new Item { Id = 2, SensorId = 5, Value = 49.2, CreatedOn = new DateTime(2012, 11, 15, 17, 48, 0, DateTimeKind.Utc) },
new Item { Id = 3, SensorId = 8, Value = 33.2, CreatedOn = new DateTime(2012, 11, 15, 17, 49, 0, DateTimeKind.Utc) },
new Item { Id = 4, SensorId = 5, Value = 48.5, CreatedOn = new DateTime(2012, 11, 15, 17, 49, 0, DateTimeKind.Utc) },
new Item { Id = 5, SensorId = 8, Value = 31.8, CreatedOn = new DateTime(2012, 11, 15, 17, 50, 0, DateTimeKind.Utc) },
new Item { Id = 6, SensorId = 5, Value = 42.5, CreatedOn = new DateTime(2012, 11, 15, 17, 50, 0, DateTimeKind.Utc) },
new Item { Id = 7, SensorId = 8, Value = 36.5, CreatedOn = new DateTime(2012, 11, 15, 17, 51, 0, DateTimeKind.Utc) },
new Item { Id = 8, SensorId = 5, Value = 46.5, CreatedOn = new DateTime(2012, 11, 15, 17, 51, 0, DateTimeKind.Utc) },
new Item { Id = 9, SensorId = 8, Value = 39.2, CreatedOn = new DateTime(2012, 11, 15, 17, 52, 0, DateTimeKind.Utc) },
new Item { Id = 10, SensorId = 5, Value = 44.4, CreatedOn = new DateTime(2012, 11, 15, 17, 52, 0, DateTimeKind.Utc) },
new Item { Id = 11, SensorId = 8, Value = 36.5, CreatedOn = new DateTime(2012, 11, 15, 17, 53, 0, DateTimeKind.Utc) },
new Item { Id = 12, SensorId = 5, Value = 46.5, CreatedOn = new DateTime(2012, 11, 15, 17, 53, 0, DateTimeKind.Utc) },
new Item { Id = 13, SensorId = 8, Value = 39.2, CreatedOn = new DateTime(2012, 11, 15, 17, 54, 0, DateTimeKind.Utc) },
new Item { Id = 14, SensorId = 5, Value = 44.4, CreatedOn = new DateTime(2012, 11, 15, 17, 54, 0, DateTimeKind.Utc) },
};
var interval = TimeSpan.FromMinutes(3);
var startDate = data.First().CreatedOn;
var endDate = data.Last().CreatedOn;
var numberOfPoints = (int)((endDate - startDate + interval).Ticks / interval.Ticks);
var points = Enumerable.Range(0, numberOfPoints).Select(x => startDate.AddTicks(interval.Ticks * x));
var query = from item in data
group item by item.SensorId
into g
from point in points
let itemToUse = g.LastOrDefault(x => x.CreatedOn <= point)
orderby itemToUse.CreatedOn, g.Key
select new
{
itemToUse.CreatedOn,
itemToUse.Value,
SensorId = g.Key
};
var results = query.ToList();
Assert.AreEqual(6, results.Count);
Assert.AreEqual(data[1].CreatedOn, results[0].CreatedOn);
Assert.AreEqual(data[1].Value, results[0].Value);
Assert.AreEqual(data[1].SensorId, results[0].SensorId);
Assert.AreEqual(data[0].CreatedOn, results[1].CreatedOn);
Assert.AreEqual(data[0].Value, results[1].Value);
Assert.AreEqual(data[0].SensorId, results[1].SensorId);
Assert.AreEqual(data[7].CreatedOn, results[2].CreatedOn);
Assert.AreEqual(data[7].Value, results[2].Value);
Assert.AreEqual(data[7].SensorId, results[2].SensorId);
Assert.AreEqual(data[6].CreatedOn, results[3].CreatedOn);
Assert.AreEqual(data[6].Value, results[3].Value);
Assert.AreEqual(data[6].SensorId, results[3].SensorId);
Assert.AreEqual(data[13].CreatedOn, results[4].CreatedOn);
Assert.AreEqual(data[13].Value, results[4].Value);
Assert.AreEqual(data[13].SensorId, results[4].SensorId);
Assert.AreEqual(data[12].CreatedOn, results[5].CreatedOn);
Assert.AreEqual(data[12].Value, results[5].Value);
Assert.AreEqual(data[12].SensorId, results[5].SensorId);
}
}
Here's how you can do it in two calls to the database (untested):
int interval = 10;
DateTime firstDate = db.Items.Select(x => x.CreatedOn).Min();
var items = db.Items.Where(x => (x.CreatedOn - firstDate).TotalMinutes % interval == 0).ToList();
Have a list like this:
01/01/2009, 120
04/01/2009, 121
30/12/2009, 520
01/01/2010, 100
04/01/2010, 101
31/12/2010, 540
I need to find the last value for each year, e.g. the result would be 520, 540?
var lastValues = records.OrderByDescending(r => r.Date)
.GroupBy(r => r.Date.Year)
.Select(g => g.First().Value);
class Program
{
static void Main()
{
var list = new[]
{
new { Date = new DateTime(2009, 1, 1), Value = 120 },
new { Date = new DateTime(2009, 4, 1), Value = 121 },
new { Date = new DateTime(2009, 12, 30), Value = 520 },
new { Date = new DateTime(2010, 1, 1), Value = 100 },
new { Date = new DateTime(2009, 4, 1), Value = 101 },
new { Date = new DateTime(2010, 12, 31), Value = 540 },
};
var result = list
.GroupBy(x => x.Date.Year)
.Select(g => new { Date = g.Key, MaxValue = g.Max(x => x.Value) });
foreach (var item in result)
{
Console.WriteLine(item);
}
}
}