I would like to create a simple linq query, but I don't really know, how it should be. I have searched the net, but found nothing, what I can use or I don't know yet, that I could use it.
So, basically, I have a table with this fields: reference, vat_code, amount, vat_amount, supplier.
Now, I would like to query the records, where reference<>'' and the reference is more than once in the table. But I need all the occupians.
F.e. from
1;VF;100;27;345
2;VF;200;54;123
2;VF;-200;-54;123
2;VF;200;54;123
3;VF;300;81;888
to
2;VF;200;54;123
2;VF;-200,-54;123
2;VF;200;54;123
How would be look the linq query to this?
Thanks.
If rows with same reference should go together in results, then you should filter out rows with reference equal to empty string, then group all rows by reference and select only those groups which have more than one row.
C# sample with DataTable:
var result = dt.AsEnumerable()
.Where(r => r.Field<string>("reference") != "")
.GroupBy(r => r.Field<string>("reference"))
.Where(g => g.Count() > 1)
.SelectMany(g => g); // flatten group to sequence of rows
Related
I am trying to get a list of a database table called oracleTimeCards whose employee id equals to the employeeID in employees list. Here is what I wrote:
LandornetSQLEntities db = new LandornetSQLEntities();
List<OracleEmployee> employees = db.OracleEmployees.Where(e => e.Office.Contains(officeName) && e.IsActive == true).Distinct().ToList();
var oracleTimeCards = db.OracleTimecards.Where(c => employees.Any(e => c.PersonID == e.PersonID)).ToList();
Anyone has any idea?
I'm going to assume you're using Entity Framework here. You can't embed calls to arbitrary LINQ extension methods inside your predicate, since EF might not know how to translate these to SQL.
Assuming you want to find all the timecards for the employees you found in your first query, you have two options. The simplest is to have a navigation property on your Employee class, named let's say TimeCards, that points to a collection of time card records for the given employee. Here's how that would work:
var oracleTimeCards = employees
.SelectMany(e => e.TimeCards)
.ToList();
If you don't want to do this for whatever reason, you can create an array of employee IDs by evaluating your first query, and use this to filter the second:
var empIDs = employees
.Select(e => e.PersonID)
.ToArray();
var oracleTimeCards = db.OracleTimecards
.Where(tc => empIDs.Contains(tc.PersonID))
.ToList();
I have a list of record that I picked up through the code:
var list= NhSession.QueryOver<Data.Models.MembModel>()
.Where(w => w.Comp.Id == idcomp)
.JoinQueryOver(jq => jq.Ver)
.Select(s => s.Ver)
.List<Dados.Models.VerModel>();
With this code I get a list of VerModel that I have relation in a MembModel. The problem is that I what get the list of VerModel that don't be in relation in a MembModal, I think to describe this, I want to select one list that is "notin" a first list. How can I do this?
Tks
What we need, as you said, is a NOT IN (subquery) statement. And NHibernate does have a clear way how to achieve that. First the subquery, which will return MembModel collection (filtered or not - as needed), represented by the VerModel.ID
var subquery = QueryOver.Of<Data.Models.MembModel>()
// we can still filter this sub-select ... or not
// .Where(w => w.Comp.Id == idcomp)
// what we need to be returned is the reference id, the VerModel.ID
.Select(m => m.Ver.ID);
And now we will query the VerModel itself, with the NOT IN (subquery) clause:
var list = session.QueryOver<Dados.Models.VerModel>()
.WithSubquery
.WhereProperty(v => v.ID) // the ID to match the prev selected one
.NotIn(subquery) // should NOT be IN
.List<Dados.Models.VerModel>();
Check:
16.8. Subqueries
My table has following columns:-
LevelId, LevelName, ScenarioId, TeamId.
I want to select LevelName corresponding to minimum LevelId when grouped by teamId
So, you want to:
Group by team ID
Within each group, order by level ID
Take the first result's level name
So that sounds like:
var query = table.GroupBy(x => x.TeamId)
.Select(g => g.OrderBy(x => x.LevelId).First().Name);
Don't just take this query and include it in your code though - make sure you understand it so you can come up with your own solution next time you have something similar to do.
If this is in LINQ to Objects, you may find that MoreLINQ would be useful, with its MinBy method:
var query = table.GroupBy(x => x.TeamId)
.Select(g => g.MinBy(x => x.LevelId).Name);
This avoids ordering the whole group, just to find the entry with the minimum level ID.
I am trying to select multiple columns from an entity object but I want 1 property to be distinct. I am very new to both LINQ and Entity Framework so any help will be useful.
Here is my LINQ query so far:
var listTypes = (from s in context.LIST_OF_VALUES
orderby s.SORT_INDEX
select new { s.LIST_TYPE, s.DISPLAY_TEXT });
I want s.LIST_TYPE to be distinct. I figure using the groupby keyword is what I want (maybe?) but I have not found a way to use it that works.
Thank you.
Assuming DISPLAY_TEXT matches LIST_TYPE somehow (so you don't lose any information):
var distinct = context.LIST_OF_VALUES
.OrderBy(s => s.SORT_INDEX)
.GroupBy(s => s.LIST_TYPE)
.Select(g => new { g.Key, g.First().DISPLAY_TEXT });
A few days ago I asked a question about returning select fields from a LINQ query. Now, I want to add some grouping to the results and things are not working out.
The following query returns the correct rows but I want to limit the fields returned. For example, I only want to see the Id and Name fields.
var contactsFromDealers = Contacts.Where(x => x.ContactTypeID == 2).GroupBy (x => x.OrganizationName)
and appending .Select (x => x.Id, x.OrganizationName) doesn't help.
Any suggestions? Thanks!
you need the select before the group by i believe.
try .Select( x => new { x.Name } )