Is there any difference in performance for linq in following case:
db.Table1.Where(p=>p.Item == 2).Join(db.Table2).Where(pq => q.Item == 3).Join(db.Table3).Where(pqr.r.Item == 3)
vs
db.Table1.Join(db.Table2).Join(db.Table3).Where(pqr => pq.p.Item == 2 && pqr => pq.q.Item == 3 && pqr.r.Item == 3)
Related
I hope you are well. Is it possible to query the LazyCache cache using Linq?
// Initialize Class
retVal = (ModelXyz)MemoryCache.Default.Where(u => (u.Value is ModelXyz) &&
(u.Value as ModelXyz).Property1 == abc &&
(u.Value as ModelXyz).Property2 == cde &&
(u.Value as ModelXyz).Property3 == true).Select(x => x.Value).FirstOrDefault();
I want to return a customer which is in this city and buy ItemID = 1, 2 or NULL
List<int?> AcceptableValues = new List<int?>
{
1,2
};
List<Customer> Customers = ListOfCustomer.Where(x => x.CountryTbl.City == 1
&& x.ItemTbl.Any(p => p.ItemID == 1 || p.ItemID ==2 || p.Item is null)
&& x.SellTbl.SellType == 10).ToList();
Is there any way we can use LINQ to filter the customer who only buys itemID in the AcceptableValues ?
I've tried with ItemTbl.SingleOrDefault, or ItemTbl.Where, or AppeptableValues.Contains(m => m.ItemID) but didn't work.
List<Customer> Customers = ListOfCustomer
.Where(c => c.CountryTbl.City == 1
&& c.ItemTbl.Any(i => i.ItemID == null || AcceptableValues.Contains(i.ItemID))
&& c.SellTbl.SellType == 10).ToList();
I'm busy rewriting a system and are using Linq queries to extract data from the database. I am used to plain old TSQL and stored procedures so my Linq skills are not the best.
I have a sql query that I try to rewrite in Linq that contains a join, where clause and IN statements. I do get it right but when I run the sql query I get a different value as from the Linq query. Somewhere I'm missing something and can't find the reason.
Here is the SQL:
select
isnull(Sum(QtyCC) + Sum(QtyEmployee), 0) *
isnull(Sum(UnitPrice), 0)[TotalRValue]
from
tbl_app_KGCWIssueLines a
inner join tbl_app_KGCWIssue b on b.IssueNrLnk = a.IssueNrLnk
where
b.CreationDate >= '2011-02-01' and
a.IssueNrLnk IN (
select
IssueNrLnk
from
tbl_app_KGCWIssue
where
CustomerCode = 'PRO002' and
ISNULL(Tier1,'') = 'PRO002' and
ISNULL(Tier2,'') = 'HAMD01' and
ISNULL(Tier3,'') = '02' and
ISNULL(Tier4,'') = '02001' and
ISNULL(Tier5,'') = 'PTAHQ001' and
ISNULL(Tier6,'') = '035' and
ISNULL(Tier7,'') = '' and
ISNULL(Tier8,'') = '' and
ISNULL(Tier9,'') = '' and
ISNULL(Tier10,'') = ''
)
And here is the Linq:
ctx.ObjectContext.tbl_app_KGCWIssue
.Join(ctx.ObjectContext.tbl_app_KGCWIssueLines,
i => i.IssueNrLnk, l => l.IssueNrLnk, (i, l) => new { i, l })
.Where(o => o.i.CreationDate >= IntervalStartDate)
.Where(p => ctx.ObjectContext.tbl_app_KGCWIssue
.Where(a =>
a.CustomerCode == CustomerCode &&
a.Tier1 == employee.Tier1 &&
a.Tier2 == employee.Tier2 &&
a.Tier3 == employee.Tier3 &&
a.Tier4 == employee.Tier4 &&
a.Tier5 == employee.Tier5 &&
a.Tier6 == employee.Tier6 &&
a.Tier7 == employee.Tier7 &&
a.Tier8 == employee.Tier8 &&
a.Tier9 == employee.Tier9 &&
a.Tier10 == employee.Tier10)
.Select(i => i.IssueNrLnk)
.Contains(p.l.IssueNrLnk))
.Sum(p => p.l.UnitPrice * (p.l.QtyEmployee + p.l.QtyCC));
I'm trying to construct a Linq statement to be used from a client with the Sharepoint (2010) object model.
This is the problematic piece of code:
var result = news.Where(n => (bool)n["Online"]
&& ((DateTime)n["StartDate"] <= DateTime.Now && (DateTime)n["StopDate"] >= DateTime.Now));
if (currentUser.IsAgUser())
result = result.Where(n => (string)n["Role"] != "AG-ADMIN");
var filteredNews = sharepointContext.LoadQuery(result);
When the if parte is executed and so another Where is added to result, I get the followin error when LoadQuerying it.
The query expression 'value(Microsoft.SharePoint.Client.ListItemCollection).Where(n => (Convert(n.get_Item("Online")) AndAlso ((Convert(n.get_Item("StartDate")) <= DateTime.Now) AndAlso (Convert(n.get_Item("StopDate")) >= DateTime.Now)))).Where(n => (Convert(n.get_Item("Role")) != "AG-ADMIN"))' is not supported.
Where is the error coming from? Thanks
It seems like SharePoint doesn't support several wheres.
Cheap solution:
var result = currentUser.IsAgUser()
? news.Where(n => (bool)n["Online"]
&& ((DateTime)n["StartDate"] <= DateTime.Now && (DateTime)n["StopDate"] >= DateTime.Now) && (string)n["Role"] != "AG-ADMIN")
: news.Where(n => (bool)n["Online"]
&& ((DateTime)n["StartDate"] <= DateTime.Now && (DateTime)n["StopDate"] >= DateTime.Now));
var filteredNews = sharepointContext.LoadQuery(result);
I am trying to do a search with LINQ to NHibernate.
I have this code:
from d in rep.QueryAll<Document>()
where
d.Plata != null && d.Contractant != null && d.Stadiu == StadiuDocument.Polita
&& (d.NrPolita.Contains(query) ||
d.Contractant.CodUnic.Contains(query) ||
d.Contractant.Denumire.Contains(query) ||
d.Plata.IdTranzactie.Contains(query)) &&
((TipPolita != null) ? (d.Tip == (TipProdus)TipPolita) : (1 == 1)) &&
((StareDocument != null) ? (d.Stare == (StareDocument)StareDocument) : (1 == 1))
select new
{
The problem is that I have some select inputs that have general values. Something like this:
<select id="tippolita" >
<option value = "-1">Any value</option>
<option value = "1">Value 1</option>
<option value = "2">Value 2</option>
<option value = "3">Value 3</option>
</select>
So when "Any value" is selected the where statement should be true like I wrote here:
((TipPolita != null) ? (d.Tip == (TipProdus)TipPolita) : (1 == 1)) &&
((StareDocument != null) ? (d.Stare == (StareDocument)StareDocument) : (1 == 1))
This is almost the same as what I would write in SQL.
An error occurs inside the Nhibernate source code at line 33 in the file "Linq\NHLinqExpression.cs"
_expression = PartialEvaluatingExpressionTreeVisitor.EvaluateIndependentSubtrees(expression);
This error actually comes from the re-linq library.
One obvious workaround is to just write 3 if statements and put the appropriate LINQ queries in each of them but that means writing a lot more code.
Is there any way to make this kind of query work without copy-pasting the entire query and modifying just a little of it?
P.S.
This is the inner exception:
InnerException: System.NullReferenceException
Message=Object reference not set to an instance of an object.
Source=Anonymously Hosted DynamicMethods Assembly
StackTrace:
at lambda_method(Closure
)
I would rewrite this:
((TipPolita != null) ? (d.Tip == (TipProdus)TipPolita) : (1 == 1)) &&
((StareDocument != null) ? (d.Stare == (StareDocument)StareDocument) : (1 == 1))
as
(TipPolita == null || d.Tip == (TipProdus)TipPolita) &&
(StareDocument == null || d.Stare == (StareDocument)StareDocument)
I don't know whether it'll work in NHibernate or not, but it's more idiomatic C# at least, so I would expect that it's more likely to be supported.
As an alternative, you could just replace "1 == 1" with "true".
Well, figured out how to do this the proper way
var date = rep.QueryAll<Document>().Where(d => d.Plata != null && d.Contractant != null && d.Stadiu == StadiuDocument.Polita);
if (!string.IsNullOrEmpty(query))
date = date.Where(d => (d.NrPolita.Contains(query) ||
d.Contractant.CodUnic.Contains(query) ||
d.Contractant.Denumire.Contains(query)));
I just move the ifs into the code and build the query(or rather the IQueryable) bit by bit