Develop Reference

Linq to Entities - Query to check for match on "n" number of characters from input

I want to bring back a set of results based on the characters typed in by a user.
I've created the following query which does what I want inside of LINQpad4
LinqPad
var PostCodes = (from OA in OrganisationAddresses
join OV in OpportunityVersions on OA.ID equals OV.LocationID
where OA.CurrentVersion.PostCode.Contains("LH")
select OV.ID).ToList();
PostCodes.Dump();
The user enters the string of "LH" and I get 13 results back
Now when I place a very similar query into my production environment, if I type in "LH" I get zero results. it only returns matches when the full string is entered such as "LH1 1HP"
Production
Builder = Builder.And(o =>
(from OA in Context.OrganisationAddresses
join OV in Context.OpportunityVersions on OA.ID equals OV.LocationID
where Options.PostCode.Contains(OA.CurrentVersion.PostCode)
&& OV.ID == o.CurrentVersionID select OV.ID).Any());
I am using SQLServer2012 and LINQ to Entities. I would like to know what could be causing this and how to fix it.
Thanks

It seems you swapped some code by mistake
Builder = Builder.And(o =>
(from OA in Context.OrganisationAddresses
join OV in Context.OpportunityVersions on OA.ID equals OV.LocationID
where OA.CurrentVersion.PostCode.Contains(Options.PostCode) // fix in this string
&& OV.ID == o.CurrentVersionID select OV.ID).Any());
And also you have additional condition in prod:
&& OV.ID == o.CurrentVersionID

What is lambda equivalent an SQL "in" statement?

I can't figure out a lambda equivalent of this sql statement:
select * from Document
where Document.OrginalDocumentNumber
in (select documentAccess.DocumentId from documentAccess where userId='1')
The problem is that Document & documentaccess tables have no relation to each other.
Any help would be so much appreciated.

Replace IN with EXISTS and you get following:
from d in dbContext.Documents
where dbContext.documentAccesses.Any(
x=>x.DocumentId == d.OrginalDocumentNumber && x.userId == '1' )
select d

Normally, if you have sensible navigation properties, you can avoid join or sub-queries directly:
var documents = from documentAccess in contex.DocumentAccesses
where documentAccess.UserId == 1
select documentAccess.Document;
You may want to use .Distinct() on the results, depending on your data.
Similarly:
var documents = contex.DocumentAccesses
.Where(access => access.UserId == 1)
.Select(access => access.Document);
And even better, if you already have a User in context:
var documents = currentUser.DocumentAccesses.Select(access => access.Document);

LINQ Projected Filtering C#

I want to filter my LINQ query based on an included table but am having some trouble.
Here is the original statement, which works:
return
this.ObjectContext.People.
Include("Careers").
Include("Careers.Titles").
Include("Careers.Titles.Salaries");
Now I'm trying to filter on Careers using projected filtering but am having trouble. It compiles but it leaves out the Titles and Salaries tables, which causes runtime errors, and I can't seem to add those tables back in:
var query1 = (
from c in
this.ObjectContext.People.
Include("Careers").
Include("Careers.Titles").
Include("Careers.Titles.Salaries")
select new
{
c,
Careers = from Careers in c.Careers
where Careers.IsActive == true
select Careers
});
var query = query1.AsEnumerable().Select(m => m.c);
return query.AsQueryable();
How can I include the titles and salaries tables in the filtered query?

You can simplify your query considerably, which should resolve your issue. I'm assuming that you want all people with at least 1 active career:
var query =
from c in
this.ObjectContext.People.
Include("Careers").
Include("Careers.Titles").
Include("Careers.Titles.Salaries")
where c.Careers.Any(c => c.IsActive);
return query;

I would try something like,
var query = from p in ObjectContext.People
join c in ObjectContext.Careers on p equals c.Person
where c.IsActive
select p;

using "greater than or equal" operator in linq join operation [duplicate]

I had tried to join two table conditionally but it is giving me syntax error. I tried to find solution in the net but i cannot find how to do conditional join with condition. The only other alternative is to get the value first from one table and make a query again.
I just want to confirm if there is any other way to do conditional join with linq.
Here is my code, I am trying to find all position that is equal or lower than me. Basically I want to get my peers and subordinates.
from e in entity.M_Employee
join p in entity.M_Position on e.PostionId >= p.PositionId
select p;

You can't do that with a LINQ joins - LINQ only supports equijoins. However, you can do this:
var query = from e in entity.M_Employee
from p in entity.M_Position
where e.PostionId >= p.PositionId
select p;
Or a slightly alternative but equivalent approach:
var query = entity.M_Employee
.SelectMany(e => entity.M_Position
.Where(p => e.PostionId >= p.PositionId));

Following:
from e in entity.M_Employee
from p in entity.M_Position.Where(p => e.PostionId >= p.PositionId)
select p;
will produce exactly the same SQL you are after (INNER JOIN Position P ON E..PostionId >= P.PositionId).

var currentDetails = from c in customers
group c by new { c.Name, c.Authed } into g
where g.Key.Authed == "True"
select g.OrderByDescending(t => t.EffectiveDate).First();
var currentAndUnauthorised = (from c in customers
join cd in currentDetails
on c.Name equals cd.Name
where c.EffectiveDate >= cd.EffectiveDate
select c).OrderBy(o => o.CoverId).ThenBy(o => o.EffectiveDate);
If you have a table of historic detail changes including authorisation status and effective date. The first query finds each customers current details and the second query adds all subsequent unauthorised detail changes in the table.
Hope this is helpful as it took me some time and help to get too.

is there a better way to write this frankenstein LINQ query that searches for values in a child table and orders them by relevance?

I have a table of Users and a one to many UserSkills table. I need to be able to search for users based on skills. This query takes a list of desired skills and searches for users who have those skills. I want to sort the users based on the number of desired skills they posses. So if a users only has 1 of 3 desired skills he will be further down the list than the user who has 3 of 3 desired skills.
I start with my comma separated list of skill IDs that are being searched for:
List<short> searchedSkillsRaw = skills.Value.Split(',').Select(i => short.Parse(i)).ToList();
I then filter out only the types of users that are searchable:
List<User> users = (from u in db.Users
where
u.Verified == true &&
u.Level > 0 &&
u.Type == 1 &&
(u.UserDetail.City == city.SelectedValue || u.UserDetail.City == null)
select u).ToList();
and then comes the crazy part:
var fUsers = from u in users
select new
{
u.Id,
u.FirstName,
u.LastName,
u.UserName,
UserPhone = u.UserDetail.Phone,
UserSkills = (from uskills in u.UserSkills
join skillsJoin in configSkills on uskills.SkillId equals skillsJoin.ValueIdInt into tempSkills
from skillsJoin in tempSkills.DefaultIfEmpty()
where uskills.UserId == u.Id
select new
{
SkillId = uskills.SkillId,
SkillName = skillsJoin.Name,
SkillNameFound = searchedSkillsRaw.Contains(uskills.SkillId)
}),
UserSkillsFound = (from uskills in u.UserSkills
where uskills.UserId == u.Id && searchedSkillsRaw.Contains(uskills.SkillId)
select uskills.UserId).Count()
} into userResults
where userResults.UserSkillsFound > 0
orderby userResults.UserSkillsFound descending
select userResults;
and this works! But it seems super bloated and inefficient to me. Especially the secondary part that counts the number of skills found.
Thanks for any advice you can give.
--r

I think that should do the trick:
(from u in users
where u.UserSkills.Any(skill => searchedSkillsRaw.Contains(skill.SkillId))
select new
{
u.Id,
u.FirstName,
u.LastName,
u.UserName,
UserPhone = u.UserDetail.Phone,
UserSkills = u.UserSkills,
UserSkillsFound = u.UserSkills.Where(skill => searchedSkillsRaw.Contains(skill.SkillId)).Count()
} into userResults
orderby userResults.UserSkillsFound descending
select userResult).ToList();
However, since this is a query that gets executed on SQL server I strongly recommend to remove the 'ToList()' call from the first query. Because that actually causes LINQ to run two separate queries on the SQL server. You should change it to IQueryable instead. The power of LINQ is to construct queries in several steps without having to actually execute it in between. So 'ToList' should be called only at the end when the entire query has been constructed. In fact what you currently do is running the second query in memory rather than on the database server.
In regards to your UserSkills one-to-many relation you do not need to do an explicity join in LINQ. You can just access the collection property instead.
Let me know if you need more explanation.
Michael

Why not just let people do, say, fUsers.UserSkills.Count()? It would reduce the amount of data retrieved from the server in the first place.
Alternatively, you could create a View that has a calculated field in it and then map that to a type. Would push the query for count down into the DB.