I need to return a distinct list of records based on a car keywords search like: "Alfa 147"
The problem is that, as I have 3 "Alfa" cars, it returns 1 + 3 records (it seems 1 for the Alfa and 147 result, and 3 for the Alfa result)
EDIT:
The SQL-Server Query look something like this:
SELECT DISTINCT c.Id, c.Name /*, COUNT(Number of Ads in the KeywordAdCategories table with those 2 keywords) */
FROM Categories AS c
INNER JOIN KeywordAdCategories AS kac ON kac.Category_Id = c.Id
INNER JOIN KeywordAdCategories AS kac1 ON kac.Ad_Id = kac1.Ad_Id AND kac1.Keyword_Id = (SELECT Id FROM Keywords WHERE Name = 'ALFA')
INNER JOIN KeywordAdCategories AS kac2 ON kac1.Ad_Id = kac2.Ad_Id AND kac2.Keyword_Id = (SELECT Id FROM Keywords WHERE Name = '147')
My LINQ query is:
var query = from k in keywordQuery where splitKeywords.Contains(k.Name)
join kac in keywordAdCategoryQuery on k.Id equals kac.Keyword_Id
join c in categoryQuery on kac.Category_Id equals c.Id
join a in adQuery on kac.Ad_Id equals a.Id
select new CategoryListByKeywordsDetailDto
{
Id = c.Id,
Name = c.Name,
SearchCount = keywordAdCategoryQuery.Where(s => s.Category_Id == c.Id).Where(s => s.Keyword_Id == k.Id).Distinct().Count(),
ListController = c.ListController,
ListAction = c.ListAction
};
var searchResults = new CategoryListByBeywordsListDto();
searchResults.CategoryListByKeywordsDetails = query.Distinct().ToList();
The entities are:
public class Keyword
{
// Primary properties
public int Id { get; set; }
public string Name { get; set; }
}
// Keyword Sample Data:
// 1356 ALFA
// 1357 ROMEO
// 1358 145
// 1373 147
public class Category
{
// Primary properties
public int Id { get; set; }
public string Name { get; set; }
}
// Category Sample Data
// 1 NULL 1 Carros
// 2 NULL 1 Motos
// 3 NULL 2 Oficinas
// 4 NULL 2 Stands
// 5 NULL 1 Comerciais
// 8 NULL 1 Barcos
// 9 NULL 1 Máquinas
// 10 NULL 1 Caravanas e Autocaravanas
// 11 NULL 1 Peças e Acessórios
// 12 1 1 Citadino
// 13 1 1 Utilitário
// 14 1 1 Monovolume
public class KeywordAdCategory
{
[Key]
[Column("Keyword_Id", Order = 0)]
public int Keyword_Id { get; set; }
[Key]
[Column("Ad_Id", Order = 1)]
public int Ad_Id { get; set; }
[Key]
[Column("Category_Id", Order = 2)]
public int Category_Id { get; set; }
}
// KeywordAdCategory Sample Data
// 1356 1017 1
// 1356 1018 1
// 1356 1019 1
// 1357 1017 1
// 1357 1018 1
// 1357 1019 1
// 1358 1017 1
// 1373 1019 1
public class Ad
{
// Primary properties
public int Id { get; set; }
public string Title { get; set; }
public string TitleStandard { get; set; }
public string Version { get; set; }
public int Year { get; set; }
public decimal Price { get; set; }
// Navigation properties
public Member Member { get; set; }
public Category Category { get; set; }
public IList<Feature> Features { get; set; }
public IList<Picture> Pictures { get; set; }
public IList<Operation> Operations { get; set; }
}
public class AdCar : Ad
{
public int Kms { get; set; }
public Make Make { get; set; }
public Model Model { get; set; }
public Fuel Fuel { get; set; }
public Color Color { get; set; }
}
// AdCar Sample Data
// 1017 Alfa Romeo 145 1.6TDI 2013 ALFA ROMEO 145 1.6TDI 2013 12 2 1.6TDI 1000 1 2013 1 20000,0000 2052 AdCar
// 1018 Alfa Romeo 146 1.6TDI 2013 ALFA ROMEO 146 1.6TDI 2013 12 2 5 1.6TDI 1000 2 2013 1 20000,0000 2052 AdCar
// 1019 Alfa Romeo 147 1.6TDI 2013 ALFA ROMEO 147 1.6TDI 2013 12 2 6 1.6TDI 1000 3 2013 1 20000,0000 2052 AdCar
The result I expect for the search of "ALFA" is "Cars: 3" and for the search of "ALFA 147" is "Cars: 1" and actually the result I get is "Cars: 1 \n Cars: 3"
The kac is not filtering words... so this joins of kac, kac1 and kac2 will return 3 lines, cause this is the numbers of keywords for this ad
You should remove it..
Try this:
SELECT DISTINCT
c.Id, c.Name /*, COUNT(Number of Ads in the KeywordAdCategories table with those 2 keywords) */
FROM
Categories AS c
INNER JOIN
KeywordAdCategories AS kac1 ON kac1.Keyword_Id = (SELECT Id
FROM Keywords
WHERE Name = 'ALFA')
AND kac1.Category_Id = c.Id
INNER JOIN
KeywordAdCategories AS kac2 ON kac1.Ad_Id = kac2.Ad_Id
AND kac2.Keyword_Id = (SELECT Id
FROM Keywords
WHERE Name = '147')
AND kac2.Category_Id = c.Id
I did a test...
Setting the ambient as
declare #Keywords table(id int,name varchar(max))
insert into #Keywords(id,name)
values (1356,'ALFA')
,(1357,'ROMEO')
,(1358,'145')
,(1373,'147')
declare #Categories table(id int, name varchar(max))
insert into #Categories(id,name)
values (1,'Carros')
,(2,'Motos')
declare #KeywordAdCategories table(Keyword_Id int, ad_Id int,Category_Id int)
insert into #KeywordAdCategories (Keyword_Id , ad_Id,Category_Id)
values (1356, 1017,1)
,(1356, 1018,1)
,(1356, 1019,1)
,(1357, 1017,1)
,(1357, 1018,1)
,(1357, 1019,1)
,(1358, 1017,1)
,(1373, 1019,1)
I run these two queries:
--query 1
SELECT
c.Id, c.Name,COUNT(*) as [count]
FROM
#Categories AS c
INNER JOIN
#KeywordAdCategories AS kac1 ON kac1.Keyword_Id = (SELECT Id
FROM #Keywords
WHERE Name = 'ALFA')
AND kac1.Category_Id = c.Id
GROUP BY
c.Id, c.Name
I get this result set:
Id Name count
----------- ---------- -----------
1 Carros 3
and the second query for two words...
--query 2
SELECT
c.Id, c.Name,COUNT(*) as [count]
FROM
#Categories AS c
INNER JOIN
#KeywordAdCategories AS kac1 ON kac1.Keyword_Id = (SELECT Id
FROM #Keywords
WHERE Name = 'ALFA')
AND kac1.Category_Id = c.Id
INNER JOIN
#KeywordAdCategories AS kac2 ON kac1.Ad_Id = kac2.Ad_Id
AND kac2.Keyword_Id = (SELECT Id
FROM #Keywords
WHERE Name = '147')
AND kac2.Category_Id = c.Id
GROUP BY
c.Id, c.Name
Result set is:
Id Name count
----------- ---------- -----------
1 Carros 1
Is this what you want?
You can use the Distinct() method.
var query = ...
var query = query.Distinct();
See This code returns distinct values. However, what I want is to return a strongly typed collection as opposed to an anonymous type for more details.
Split the query string into an array and iterate through querying the database for each keyword and joining the result sets using unions. The resultant set will be every distinct record that matches any of the given keywords.
Maybe this is close? At least the subqueries open it up a little for you to work with.
var query =
from c in categoryQuery
let keywords =
(
from k in keywordQuery where splitKeywords.Contains(k.Name)
join kac in keywordAdCategoryQuery on k.Id equals kac.Keyword_Id
where kac.Category_Id == c.Id
join a in adQuery on kac.Ad_Id equals a.Id
select k.Id
).Distinct()
where keywords.Any()
select new CategoryListByKeywordsDetailDto
{
Id = c.Id,
Name = c.Name,
SearchCount =
(
from kac in keywordAdCategoryQuery
where kac.Category_Id == c.Id
join kId in keywords on kac.Keyword_Id equals kId
select kac.Id
).Distinct().Count(),
ListController = c.ListController,
ListAction = c.ListAction
};
One of the beautiful features of linq is that you can build up complicated queries in smaller and simpler steps and let linq figure out how to join them all together.
The following is one way to get this information. I'm not sure whether this is the best and you would need to check it performs well when multiple keywords are selected.
Assuming keywords is defined something like
var keywords = "Alfa 147";
var splitKeywords = keywords.Split(new char[] {' '});
Stage 1
Get a list of keywords grouped by Ad and Category and
var subQuery = (from kac in keywordAdCategoryQuery
join k in keywordQuery on kac.Keyword_Id equals k.Id
select new
{
kac.Ad_Id,
kac.Category_Id,
KeyWord = k.Name,
});
var grouped = (from r in subQuery
group r by new { r.Ad_Id, r.Category_Id} into results
select new
{
results.Key.Ad_Id ,
results.Key.Category_Id ,
keywords = (from r in results select r.KeyWord)
});
Note, the classes you posted would suggest that your database does not have foreign key relationships defined between the tables. If they did then this stage would be slightly simpler to write.
Stage 2
Filter out any groups that do not have each of the keywords
foreach(var keyword in splitKeywords)
{
var copyOfKeyword = keyword ; // Take copy of keyword to avoid closing over loop
grouped = (from r in grouped where r.keywords.Contains(copyOfKeyword) select r) ;
}
Stage 3
Group by Category and count the results per category
var groupedByCategories = (from r in grouped
group r by r.Category_Id into results
join c in categoryQuery on results.Key equals c.Id
select new
{
c.Id ,
c.Name ,
Count = results.Count()
});
Stage 4
Now retrieve the information from sql. This should be done all in one query.
var finalResults = groupedByCategories.ToList();
So, if I understand the need correctly, you want all of the subset of words to be matched in the text and not the OR matching you are getting right now? I see at least two options, the first of which may not translate the split to SQL:
var query = from k in keywordQuery where !splitKeywords.Except(k.Name.split(' ')).Any()
This makes the following assumptions:
Your words in the Keywords are space delimited.
You are looking for exact matches and not partial matches. (I.e. Test will not match TestTest).
The other option being to dynamically generate a predicate using predicate builder (haven't done this in a while, my implementation might need tweaking - but this is the more likely (and better in my mind) solution):
var predicate = PredicateBuilder.True<keywordQuery>();
foreach (string s in splitKeywords) {
predicate.AND(s.Contains(k.Name));
}
query.Where(predicate);
If someone can comment if some of my syntax is off I would appreciate it. EDIT: Including link to a good reference on predicate builder: http://www.albahari.com/nutshell/predicatebuilder.aspx
UPDATE
Predicate builder across multiple tables, if anyone gets here looking for how to do that.
Can PredicateBuilder generate predicates that span multiple tables?
Should be possible to query for each keyword then union the result sets. The duplicate values will be removed from the union and you can work out the required aggregations.
Try removing the class while select
var query = (from k in keywordQuery where splitKeywords.Contains(k.Name)
join kac in keywordAdCategoryQuery on k.Id equals kac.Keyword_Id
join c in categoryQuery on kac.Category_Id equals c.Id
join a in adQuery on kac.Ad_Id equals a.Id
select new
{
Id = c.Id,
Name = c.Name,
SearchCount = keywordAdCategoryQuery.Where(s => s.Category_Id == c.Id).Where(s => s.Keyword_Id == k.Id).Distinct().Count(),
ListController = c.ListController,
ListAction = c.ListAction
}).Distinct().ToList();
var searchResults = new CategoryListByBeywordsListDto();
searchResults.CategoryListByKeywordsDetails = (from q in query select new CategoryListByKeywordsDetailDto
{
Id = q.Id,
Name = q.Name,
SearchCount = q.SearchCount,
ListController = q.ListController,
ListAction = q.ListAction
}).ToList();
You are doing a select distinct on a list of CategoryListByKeywordsDetailDto. Distinct only works on POCO and anonymous objects. In your case you need to implement the IEqualitycomparer for select distinct to work.
I tried this using LINQ directly against in memory collections (as in, not through SQL) - seems to work for me (I think the main point being that you want to search for Ads that apply to ALL the keywords specified, not ANY, correct?
Anyway, some sample code below (a little comment-ish and not necessarily the most efficient, but hopefully illustrates the point...)
Working with the following "data sets":
private List<AdCar> AdCars = new List<AdCar>();
private List<KeywordAdCategory> KeywordAdCategories = new List<KeywordAdCategory>();
private List<Category> Categories = new List<Category>();
private List<Keyword> Keywords = new List<Keyword>();
which are populated in a test method using the data you provided...
Search method looks a little like this:
var splitKeywords = keywords.Split(' ');
var validKeywords = Keywords.Join(splitKeywords, kwd => kwd.Name.ToLower(), spl => spl.ToLower(), (kwd, spl) => kwd.Id).ToList();
var groupedAdIds = KeywordAdCategories
.GroupBy(kac => kac.Ad_Id)
.Where(grp => validKeywords.Except(grp.Select(kac => kac.Keyword_Id)).Any() == false)
.Select(grp => grp.Key)
.ToList();
var foundKacs = KeywordAdCategories
.Where(kac => groupedAdIds.Contains(kac.Ad_Id))
.GroupBy(kbc => kbc.Category_Id, kac => kac.Ad_Id);
//Results count by category
var catCounts = Categories
.Join(foundKacs, cat => cat.Id, kacGrp => kacGrp.Key, (cat, kacGrp) => new { CategoryName = cat.Name, AdCount = kacGrp.Distinct().Count() })
.ToList();
//Actual results set
var ads = AdCars.Join(groupedAdIds, ad => ad.Id, grpAdId => grpAdId, (ad, grpAdId) => ad);
As I said, this is more to illustrate, please don't look too closely at the use of Joins & GroupBy etc (not sure its exactly, er, "optimal")
So, using the above, if I search for "Alfa", I get 3 Ad results, and if I search for "Alfa 147" I get just 1 result.
EDIT: I've changed the code to represent two possible outcomes (as I wasn't sure which was needed by your question)
ads will give you the actual Ads returned by the search
catCounts will give a list of anonymous types each representing the find results as a count of Ads by category
Does this help?
hi if i understand your problem correctly
"The problem is that, as I have 3 "Alfa" cars, it returns 1 + 3
records (it seems 1 for the Alfa and 147 result, and 3 for the Alfa
result)"
and Linq isn't really required i maybe have what you need just test it as new project
public Linqfilter()
{
//as Note: I modified a few classes from you because i doesn'T have your Member, Operation, Make,... classes
#region declaration
var originalAdCarList = new List<AdCar>()
{
new AdCar(){Id=1017, Title= "Alfa Romeo 145 1.6TDI 2013", Category= new Category(){Id =12}} ,
new AdCar(){Id=1018, Title= "Alfa Romeo 146 1.6TDI 2013", Category= new Category(){Id =11}} ,
new AdCar(){Id=1019, Title= "Alfa Romeo 147 1.6TDI 2013", Category= new Category(){Id =12}}
};
var originalKeywordAdCategoryList = new List<KeywordAdCategory>()
{
new KeywordAdCategory() { Keyword_Id=1356, Ad_Id=1017,Category_Id=1},
new KeywordAdCategory() { Keyword_Id=1356, Ad_Id=1018,Category_Id=1},
new KeywordAdCategory() { Keyword_Id=1356, Ad_Id=1019,Category_Id=1},
new KeywordAdCategory() { Keyword_Id=1357, Ad_Id=1017,Category_Id=1},
new KeywordAdCategory() { Keyword_Id=1357, Ad_Id=1018,Category_Id=1},
new KeywordAdCategory() { Keyword_Id=1357, Ad_Id=1019,Category_Id=1},
new KeywordAdCategory() { Keyword_Id=1358, Ad_Id=1017,Category_Id=1},
new KeywordAdCategory() { Keyword_Id=1373, Ad_Id=1019,Category_Id=1}
};
var originalCategoryList = new List<Category>()
{
new Category(){Id=1, Name="NULL 1 Carros"},
new Category(){Id=2, Name="NULL 1 Motos"},
new Category(){Id=3, Name="NULL 2 Oficinas"},
new Category(){Id=4 , Name="NULL 2 Stands"},
new Category(){Id=5 , Name="NULL 1 Comerciais"},
new Category(){Id=8, Name="NULL 1 Barcos"},
new Category(){Id=9 , Name="NULL 1 Máquinas"},
new Category(){Id=10 , Name="NULL 1 Caravanas e Autocaravanas"},
new Category(){Id=11 , Name="NULL 1 Peças e Acessórios"},
new Category(){Id=12 , Name="1 1 Citadino"},
new Category(){Id=13 , Name="1 1 Utilitário"},
new Category(){Id=14 , Name="1 1 Monovolume"}
};
var originalKeywordList = new List<Keyword>()
{
new Keyword(){Id=1356 ,Name="ALFA"},
new Keyword(){Id=1357 ,Name="ROMEO"},
new Keyword(){Id=1358 ,Name="145"},
new Keyword(){Id=1373 ,Name="147"}
};
#endregion declaration
string searchText = "ALFA";
// split the string searchText in an Array of substrings
var splitSearch = searchText.Split(' ');
var searchKeyList =new List<Keyword>();
// generate a list of Keyword based on splitSearch
foreach (string part in splitSearch)
if(originalKeywordList.Any(key => key.Name == part))
searchKeyList.Add(originalKeywordList.First(key => key.Name == part));
// generate a list of KeywordAdCategory based on searchKList
var searchKACList = new List<KeywordAdCategory>();
foreach(Keyword key in searchKeyList)
foreach (KeywordAdCategory kAC in originalKeywordAdCategoryList.Where(kac => kac.Keyword_Id == key.Id))
searchKACList.Add(kAC);
var groupedsearchKAClist = from kac in searchKACList group kac by kac.Keyword_Id;
var listFiltered = new List<AdCar>(originalAdCarList);
//here starts the real search part
foreach (IGrouping<int, KeywordAdCategory> kacGroup in groupedsearchKAClist)
{
var listSingleFiltered = new List<AdCar>();
// generate a list of AdCar that matched the current KeywordAdCategory filter
foreach (KeywordAdCategory kac in kacGroup)
foreach (AdCar aCar in originalAdCarList.Where(car => car.Id == kac.Ad_Id))
listSingleFiltered.Add(aCar);
var tempList = new List<AdCar>(listFiltered);
// iterrates over a temporary copie of listFiltered and removes items which don't match to the current listSingleFiltered
foreach (AdCar aC in tempList)
if (!listSingleFiltered.Any(car => car.Id == aC.Id))
listFiltered.Remove(aC);
}
var AdCarCount = listFiltered.Count; // is the count of the AdCar who match
var CatDic =new Dictionary<Category, int>(); // will contain the Counts foreach Categorie > 0
foreach(AdCar aCar in listFiltered)
if(originalCategoryList.Any(cat => cat.Id ==aCar.Category.Id))
{
var selectedCat = originalCategoryList.First(cat => cat.Id == aCar.Category.Id);
if (!CatDic.ContainsKey(selectedCat))
{
CatDic.Add(selectedCat, 1);//new Category Countvalue
}
else
{
CatDic[selectedCat]++; //Category Countvalue +1
}
}
}
}
public class Keyword
{
// Primary properties
public int Id { get; set; }
public string Name { get; set; }
}
public class Category
{
// Primary properties
public int Id { get; set; }
public string Name { get; set; }
}
public class KeywordAdCategory
{
//[Key]
//[Column("Keyword_Id", Order = 0)]
public int Keyword_Id { get; set; }
//[Key]
//[Column("Ad_Id", Order = 1)]
public int Ad_Id { get; set; }
//[Key]
//[Column("Category_Id", Order = 2)]
public int Category_Id { get; set; }
}
public class Ad
{
// Primary properties
public int Id { get; set; }
public string Title { get; set; }
public string TitleStandard { get; set; }
public string Version { get; set; }
public int Year { get; set; }
public decimal Price { get; set; }
// Navigation properties
public string Member { get; set; }
public Category Category { get; set; }
public IList<string> Features { get; set; }
public IList<int> Pictures { get; set; }
public IList<string> Operations { get; set; }
}
public class AdCar : Ad
{
public int Kms { get; set; }
public string Make { get; set; }
public int Model { get; set; }
public int Fuel { get; set; }
public int Color { get; set; }
}
hopefully it will help you or someone else
Edit:
extended my Methode Linqfilter() to answer the request
Edit2:
i think that should be exactly what you are looking for
var selectedKWLinq = from kw in originalKeywordList
where splitSearch.Contains(kw.Name)
select kw;
var selectedKACLinq = from kac in originalKeywordAdCategoryList
where selectedKWLinq.Any<Keyword>(item => item.Id == kac.Keyword_Id)
group kac by kac.Keyword_Id into selectedKAC
select selectedKAC;
var selectedAdCar = from adC in originalAdCarList
where (from skAC in selectedKACLinq
where skAC.Any(kac => kac.Ad_Id == adC.Id)
select skAC).Count() == selectedKACLinq.Count()
select adC;
var selectedCategorys = from cat in originalCategoryList
join item in selectedAdCar
on cat.Id equals item.Category.Id
group cat by cat.Id into g
select g;
//result part
var AdCarCount = selectedAdCar.Count();
List<IGrouping<int, Category>> list = selectedCategorys.ToList();
var firstCategoryCount = list[0].Count();
var secoundCategoryCount = list[1].Count();
Fiuu, this was brain-wreck. I splited query in several pieces, but it's executed as a whole at the end (var result). And I returned anonymous class, but intention is clear.
Here is the solution:
var keywordIds = from k in keywordQuery
where splitKeywords.Contains(k.Name)
select k.Id;
var matchingKac = from kac in keywordAdCategories
where keywordIds.Contains(kac.Keyword_Id)
select kac;
var addIDs = from kac in matchingKac
group kac by kac.Ad_Id into d
where d.Count() == splitKeywords.Length
select d.Key;
var groupedKac = from kac in keywordAdCategoryQuery
where addIDs.Contains(kac.Ad_Id)
group kac by new { kac.Category_Id, kac.Ad_Id };
var result = from grp in groupedKac
group grp by grp.Key.Category_Id into final
join c in categoryQuery on final.Key equals c.Id
select new
{
Id = final.Key,
Name = c.Name,
SearchCount = final.Count()
};
// here goes result.ToList() or similar
Related
Hi i convert sql query to linq i got this error. when i remove group by there isn't exception but i should use group by. why i got this exception ?
public List<BiontechSinovacCovidDto> GetBiontechSinovacCovidDto()
{
using(SirketDBContext context=new SirketDBContext())
{
var result =
from asi in context.Asilar
join covid in context.Covids
on asi.CovidId equals covid.CovidId
group asi by asi.AsiIsmi into isim
select new BiontechSinovacCovidDto
{
AsiIsmi=isim.Key,
//exception OrtalamaCovidSuresi=(EF.Functions.DateDiffDay(covid.CovidYakalanmaTarih, covid.CovidBitisTarih)).Average()
};
return result.ToList();
}
}
my sql query
Select
AsiIsmi,
AVG(Cast(DATEDIFF(Day,CovidYakalanmaTarih, CovidBitisTarih)AS FLOAT)) as OrtalamaCovidSuresi
From Asilar
INNER JOIN Covids on Covids.CovidId=Asilar.CovidId
group by AsiIsmi
|AsiIsmi| OrtalamaCovidSuresi|
------- ------------------
Biontech 13.6667
Sinovac 15
BiontechSinovacCovidDto
public class BiontechSinovacCovidDto
{
public string AsiIsmi { get; set; }
public double OrtalamaCovidSuresi { get; set; }
}
Average has overload which accepts lambda. You have to use this version. Also you have to group covid in this case.
public List<BiontechSinovacCovidDto> GetBiontechSinovacCovidDto()
{
using (var context = new SirketDBContext())
{
var result =
from asi in context.Asilar
join covid in context.Covids
on asi.CovidId equals covid.CovidId
group covid by asi.AsiIsmi into isim
select new BiontechSinovacCovidDto
{
AsiIsmi = isim.Key,
OrtalamaCovidSuresi = isim.Average(x => EF.Functions.DateDiffDay(x.CovidYakalanmaTarih, x.CovidBitisTarih))
};
return result.ToList();
}
}
I need a little help in converting SQL to Linq. It's pretty straight forward in MySQL...
Table: customers
ID Name
1 Bill
2 John
Table: purchases
ID CustomerID CompletedTransaction
1 1 False
2 2 True
3 1 True
4 1 True
SELECT c.ID
c.Name,
COUNT(p.ID) AS TotalPurchases,
SUM(CASE WHEN p.CompletedTransaction = TRUE THEN 1 ELSE 0 END) AS TotalCompleted
FROM customers c
LEFT JOIN purchases p ON c.ID = p.CustomerID
GROUP BY c.ID
Expected Result:
1, Bill, 3, 2
2, John, 1, 1
I've seen a few examples on how to implement a left join in Linq but I'm not sure how to include a SUM and Count into this. I've seen examples in Linq where the fields returned are selected from the group keys. Does this mean that if I have more fields in the customers table such as address and other contact details which I'd like to return, I'd have to include them in the join to then be able to select them? Hope this makes sense. Appreciate any help or links that might point me in the right direction.
Thanks
var answer = (from c in db.customers
join p in db.purchases
on c.ID = p.CustomerID into subs
from sub in subs.DefaultIfEmpty()
group sub by new { c.ID, c.Name } into gr
select new {
gr.Key.ID,
gr.Key.Name,
Total = gr.Count(x => x != null),
CountCompleted = gr.Count(x => x != null && x.CompletedTransaction)
}).ToList();
Here's the sample
class Program
{
static void Main(string[] args)
{
List<Customers> customers = new List<Customers>();
customers.Add(new Customers() { ID = 1, Name = "Bill" });
customers.Add(new Customers() { ID = 2, Name = "John" });
List<Purchases> purchases = new List<Purchases>();
purchases.Add(new Purchases() { ID = 1, CustomerID = 1, CompletedTransaction = false });
purchases.Add(new Purchases() { ID = 2, CustomerID = 2, CompletedTransaction = true });
purchases.Add(new Purchases() { ID = 3, CustomerID = 1, CompletedTransaction = true });
purchases.Add(new Purchases() { ID = 4, CustomerID = 1, CompletedTransaction = true });
IEnumerable<JoinResult> results = from c in customers
join p in purchases
on c.ID equals p.CustomerID
group new { c, p } by new {p.CustomerID, c.Name} into r
select new JoinResult
{
CustomerID = r.Key.CustomerID,
CustomerName = r.Key.Name,
TotalPurchases = r.Count(),
TotalCompleteTransaction = r.Where(s=> s.p.CompletedTransaction).Count()
};
foreach(JoinResult r in results)
{
Console.WriteLine($"CustomerID : {r.CustomerID} | Name : {r.CustomerName} | TotalPurchases : {r.TotalPurchases} | TotalCompleteTransaction : {r.TotalCompleteTransaction}");
}
Console.ReadKey();
}
}
class Customers
{
public int ID { get; set; }
public string Name { get; set; }
}
class Purchases
{
public int ID { get; set; }
public int CustomerID { get; set; }
public bool CompletedTransaction { get; set; }
}
class JoinResult
{
public int CustomerID { get; set; }
public string CustomerName { get; set; }
public int TotalPurchases { get; set; }
public int TotalCompleteTransaction { get; set; }
}
Result
I'm running this Linq query:
var patientList = from p in db.Patients
where p.ClinicId==11
select p.Id;
var patientswithplan = from p in db.Plans
where patientList.Contains(p.PatientId)
select p;
It returns 1030 results.
But when I came up with this query I wrote it in sql first to test it out and this displays 956 results
select id from patients where clinicid=11
and id in(select patientid from plans)
order by id
I thought these queries would be the same, what is the difference, which one is correct?
I have written a little code then you could see the difference yourself
void Main()
{
var Plans = new List<Plan>();
Plans.Add(new Plan() {PatientId = 1, PlanName = "Good Plan"});
Plans.Add(new Plan() {PatientId = 2, PlanName = "Bad Plan"});
var Patients = new List<Patient>();
Patients.Add(new Patient() {ClinicId = 1, Name = "Frank"});
Patients.Add(new Patient() {ClinicId = 2, Name = "Fort"});
// This is your LINQ
var patientList = from p in Patients
where p.ClinicId == 1
select p.ClinicId;
var patientswithplan = from p in Plans
where patientList.Contains(p.PatientId)
select p;
Console.WriteLine(patientswithplan);
// We return a PLAN here
// Result
// IEnumerable<Plan> (1 item)
// PatientId 1
// PlanName Good Plan
// This is the equivalent Linq of your SQL
var myPatient = Patients.Where(
pa => pa.ClinicId == 1 &&
Plans.Any(pl => pl.PatientId == pa.ClinicId)
);
Console.WriteLine(myPatient);
// Look! We return a PATIENT here
// Result
// IEnumerable<Patient> (1 item)
// ClinicId 1
// Name Frank
}
// Define other methods and classes here
class Patient
{
public Patient() {}
public int ClinicId { get; set; }
public string Name { get; set; }
}
class Plan
{
public Plan() {}
public int PatientId { get; set; }
public string PlanName { get; set; }
}
The queries do two different things:
1) The first query is basically first getting a list of patients, and then it's fetching plans (you choose "from p in db.Plans") that have those selected patients in their list of patients.
2) The second query is filtering and fetching patients of given clinic making sure that those patients exist in some plans.
So of course the number of results will be different as you probably have a different number of rows in the patients and plans tables.
I am trying to get a list filtered based on the matches of one of the properties with a property of another list.
In below example, only the items which have common 'name' between both lists should be filtered in 1st list. Can some one tell me the most concise way of doing it?
class TCapability
{
public string Name { get; set; }
public int Id { get; set; }
}
class PCapability
{
public string Name { get; set; }
public int Code { get; set; }
}
Input:
var capability = new List<TCapability>()
{
new TCapability() {Name="a", Id=1},
new TCapability() {Name="b", Id=2},
new TCapability() {Name="c", Id=3}
};
var type2Capability = new List<PCapability>()
{
new PCapability() {Name="a", Code=100},
new PCapability() {Name="b", Code=200},
new PCapability() {Name="d", Code=300}
};
Expected Output:
capability =
{
{ Name="a", Id=1 },
{ Name="b", Id=2 }
}
var result = capability.Where(c => type2Capability.Any(c2 => c.Name == c2.Name));
you can try use join clause like this
capability = (from a in capability
join b in type2Capability on a.Name equals b.Name
select a).ToList();
UPDATE on comment if type2Capability can have duplicate names
capability = (from a in capability
join b in type2Capability on a.Name equals b.Name into f
where f.Any()
select a).ToList();
If the lists can get long then a HashSet can speed things up.
var set = new HashSet<string>(type2Capability.Select(t => t.Name));
var res = capability.Where(c => set.Contains(c.Name));
I need to make a search based on a set of keywords, that return all the Ads related with those keywords. Then the result is a list of Categories with the Ads Count for each Category.
The search is made in a KeywordSearch Table:
public class KeywordSearch
{
public int Id { get; set; }
public string Name { get; set; }
public Keyword Keyword { get; set; }
}
Where the Keyword Table is:
public class Keyword
{
public int Id { get; set; }
public string Name { get; set; }
}
The Ads are related with the Keywords using the following Table:
public class KeywordAdCategory
{
[Key]
[Column("Keyword_Id", Order = 0)]
public int Keyword_Id { get; set; }
[Key]
[Column("Ad_Id", Order = 1)]
public int Ad_Id { get; set; }
[Key]
[Column("Category_Id", Order = 2)]
public int Category_Id { get; set; }
}
Finally, the Category table:
public class Category
{
public int Id { get; set; }
public string Name { get; set; }
}
Example:
Keywords: "Mercedes-Benz" and "GLK"
KeywordSearch: "Mercedes" and "Benz" for the Keyword "Mercedes-Benz"
"GLK" for the Keyword "GLK"
Category: "Cars" and "Trucks"
Ads: Car - Mercedes-Benz GLK
Truck - Mercedes-Benz Citan
If I search "Mercedes-Benz" I get:
Cars: 1
Trucks: 1
If I search "Mercedes-Benz GLK" I get:
Cars: 1
If I search "Mercedes Citan" I get:
Trucks: 1
What I get until now:
var keywordIds = from k in keywordSearchQuery
where splitKeywords.Contains(k.Name)
select k.Keyword.Id;
var matchingKac = from kac in keywordAdCategoryQuery
where keywordIds.Distinct().Contains(kac.Keyword_Id)
select kac;
var addIDs = from kac in matchingKac
group kac by kac.Ad_Id into d
where d.Count() == splitKeywords.Count()
select d.Key;
var groupedKac = from kac in keywordAdCategoryQuery
where addIDs.Contains(kac.Ad_Id) <--- EDIT2
group kac by new { kac.Category_Id, kac.Ad_Id };
var result = from grp in groupedKac
group grp by grp.Key.Category_Id into final
join c in categoryQuery on final.Key equals c.Id
select new CategoryGetAllBySearchDto
{
Id = final.Key,
Name = c.Name,
ListController = c.ListController,
ListAction = c.ListAction,
SearchCount = final.Count()
};
The problem is that I can't get only the Ads that match all Keywords.
EDIT:
When a keyword is made of 2 or more KeywordSearches like "Mercedes-Benz", the line "where d.Count() == splitKeywords.Count()" fails, because d.count = 1 and splitkeywords.Count = 2 for "Mercedes-Benz"
Any Help?
this may not be the direct answer, but in such "multiple parameter search" situations i just forget about anything and do the simple thing, for ex: Search By Car Manufacturer, CategoryId, MillageMax, Price :
var searchResults = from c in carDb.Cars
where (c.Manufacturer.Contains(Manufacturer) || Manufacturer == null) &&
(c.CategoryId == CategoryId || CategoryId == null) &&
(c.Millage <= MillageMax || MillageMax== null) &&
(c.Price <= Price || Price == null)
select c
now if any of the parameters is null it cancels the containing line by making the whole expression in brackets True and so it does not take a part in search any more
If you try to make your own search engine you will probably fail.Why don't you try Lucene.
Here's a link http://lucenenet.apache.org/.
Cheers
I think I have a solution now. This is based on your previous question and a few assumptions:
Keywords are complete names like "Mercedes-Benz GLK", "Mercedes-Benz Citan".
KeywordSearchs are "Mercedes", "Benz" and "GLK" for "Mercedes-Benz GLK" and "Mercedes", "Benz" and "Citan" for "Mercedes-Benz Citan"
"Mercedes-Benz GLK" is a "Car", "Mercedes-Benz Citan" is a "Truck"
With those three assumptions in mind I can say that
var keywordIds = from k in keywordSearchQuery
where splitKeywords.Contains(k.Name)
select k.Keyword.Id;
is the culprit and all queries below rely on it. This query will find all keywords that contain any words in your searchstring.
Example: Given searchstring "Mercedes-Benz GLK" will be split into "Mercedes", "Benz" and "GLK". Your query now finds "Mercedes" and "Benz" in both "Mercedes-Benz GLK" and "Mercedes-Benz Citan".
I think it's obvious that you don't want "Mercedes-Benz GLK" to match "Mercedes-Benz Citan".
The solution is to tell the query to match every splitKeywords with any Keywordsearch and return the appropriate Keyword:
var keywordIds = keywordSearchQuery
.GroupBy(k => k.Keyword.Id)
.Where(g => splitKeywords.All(w =>
g.Any(k => k.Name.Contains(w))))
.Select(g => g.Key);
As for addIds changing it to var addIDs = matchingKac.Select(ad => ad.Ad_Id).Distinct(); should do the trick. Or if matchingKac is only needed in addIds then you could change it to
var matchingKac = (from kac in keywordAdCategoryQuery
where keywordIds.Distinct().Contains(kac.Keyword_Id)
select kac.Ad_Id).Distinct();
and remove addIds.
I haven't compile-checked this or anything, so it may require some tweaking, but you're looking for something along these lines.
var matchingKac = keywordIds.Distinct().ToList()
.Aggregate(
keywordAdCategoryQuery.AsQueryable(),
(q, id) => q.Where(kac => kac.Keyword_Id == id));
You're effectively saying, "Start with keywordAdCategoryQuery, and for each keyword add a .Where() condition saying that it must have that keyword in it. You could do the same thing with a for loop if you find Aggregate difficult to read.
I am suggesting you to add regex and omit that special characters and then use Linq for that
So Mercedez-Benz can become Mercedez and benz
I recommend to NOT define keywords to objects that way, because you might search and find too many objects or you'll find possibly nothing. You will always spoil your time when searching. Classify your objects in a way that the users focus is to FIND and not to search.
I have posted my answer to: https://github.com/n074v41l4bl34u/StackOverflow19796132
Feel free to review it.
Here is the most important snippet.
with:
internal class SearchDomain
{
public List<Keyword> Keywords { get; set; }
public List<Category> Categories { get; set; }
public List<KeywordAdCategory> KeywordAdCategories { get; set; }
}
then:
private static char[] keywordPartsSplitter = new char[] { ' ', '-' };
internal static Dictionary<Category, Dictionary<int, List<KeywordAdCategory>>> FromStringInput(string searchPhrase, SearchDomain searchDomain)
{
var identifiedKeywords = searchPhrase
.Split(keywordPartsSplitter);
var knownKeywordParts = identifiedKeywords
.Where
(ik =>
searchDomain
.Keywords
.SelectMany(x => x.GetKeywordParts())
.Any(kp => kp.Equals(ik, StringComparison.InvariantCultureIgnoreCase))
);
var keywordkSearches = knownKeywordParts
.Select((kkp, n) => new KeywordSearch()
{
Id = n,
Name = kkp,
Keyword = searchDomain
.Keywords
.Single
(k =>
k.GetKeywordParts()
.Any(kp => kp.Equals(kkp, StringComparison.InvariantCultureIgnoreCase))
)
});
var relevantKeywords = keywordkSearches
.Select(ks => ks.Keyword)
.Distinct();
var keywordAdCategoriesByCategory = searchDomain.Categories
.GroupJoin
(
searchDomain.KeywordAdCategories,
c => c.Id,
kac => kac.Category_Id,
(c, kac) => new { Category = c, AdKeywordsForCategory = kac }
);
var relevantKeywordAdCategories = keywordAdCategoriesByCategory
.Where
(kacbk =>
relevantKeywords
.All
(rk =>
kacbk
.AdKeywordsForCategory
.Any(kac => kac.Keyword_Id == rk.Id)
)
);
var foundAdsInCategories = relevantKeywordAdCategories
.ToDictionary
(rkac =>
rkac.Category,
rkac => rkac.AdKeywordsForCategory
.GroupBy(g => g.Ad_Id)
.ToDictionary(x => x.Key, x => x.ToList())
);
return foundAdsInCategories;
}
It does exactly what you want however I find something fishy about keywords being divisible to sub-keywords. Than again, maybe it is just the naming.