i need to write sql query in string and pass it to linq like executenonquery() in ado.net
but i need to return data from 4 tables
Example Query :
SELECT *
FROM dbo.GeneralAd INNER JOIN
dbo.Category ON dbo.GeneralAd.FkCategoryID = dbo.Category.CategoryID INNER JOIN
dbo.District ON dbo.GeneralAd.FkDistrictID = dbo.District.DistrictID LEFT OUTER JOIN
dbo.Users ON dbo.GeneralAd.FkApprovedByID = dbo.Users.UserID AND dbo.GeneralAd.FKAddedByID = dbo.Users.UserID where .........
how to return data from 4 tables with executenonquery method in linq ?
I'm not sure why you why you want to return all columns from all tables. That seems unnecessary. You can get to the District and Category fields from the GeneralAd object.
What I would probably do is define a property on the General Ad object that executes a select to get the associated User.
If you did want to do it in Linq, you could use something like this:
var results = (from ga in DataContext.GeneralAds
select new
{
Col1 = ga.Col1,
Col2 = ga.Category.Col2,
Col3 = ga.District.Col3,
Col4 = (from u in DataContext.Users
where u.UserID = ga.FkApprovedByID AND u.UserID = ga.FKAddedByID
select u.Col4)
});
You might have to add an Any() method on Col4:
var results = (from ga in DataContext.GeneralAds
select new
{
Col1 = ga.Col1,
Col2 = ga.Category.Col2,
Col3 = ga.District.Col3,
Col4 = ((from u in DataContext.Users
where u.UserID = ga.FkApprovedByID AND u.UserID = ga.FKAddedByID
select u.Col4).Any() ?
(from u in DataContext.Users
where u.UserID = ga.FkApprovedByID AND u.UserID = ga.FKAddedByID
select u.Col4).First() : -1)
});
Related
So I have few tables and i want inner join it information two create
new object. But I have a little bit trouble.
One my table have connection one to many, and when linq request , it
give me more result than i want , he just copy information. I need
request something like this:
IPagedList<HelperListings> srch = (from l in db.gp_listing
where l.DateCreated > weekago
join lp in db.gp_listing_photo on l.Id equals lp.ListingId
join loc in db.gp_location on l.LocationId equals loc.Id
orderby l.DateCreated ascending
select new HelperListings { id = l.Id, HouseNumber = l.HouseNumber,ListingPrice = l.ListingPrice, PhotoUrl = lp.PhotoUrl.First(), AreaStateCode = loc.AreaStateCode }).ToList().ToPagedList(page ?? 1, 15);
PhotoUrl = lp.PhotoUrl.First() i need something like this but i don`t have any ideas how to do it. Need ur help guys.
UPDATE :
Responding to your comment, you have at least 2 options : 1. use group by and select only the first PhotoUrl from each group, or 2. don't join to gp_listing_photo table to avoid duplicated rows, and use subquery to get only the first PhotoUrl. Example for the latter :
IPagedList<HelperListings> srch =
(from l in db.gp_listing
where l.DateCreated > weekago
join loc in db.gp_location on l.LocationId equals loc.Id
orderby l.DateCreated ascending
select new HelperListings
{
id = l.Id,
HouseNumber = l.HouseNumber,
ListingPrice = l.ListingPrice,
PhotoUrl = (from lp in db.gp_listing_photo where l.Id = lp.ListingId select lp.PhotoUrl).FirstOrDefault(),
AreaStateCode = loc.AreaStateCode
}
).ToList().ToPagedList(page ?? 1, 15);
How about simply appending .Distinct() after your LINQ query to avoid duplicated data :
IPagedList<HelperListings> srch =
(from l in db.gp_listing
where l.DateCreated > weekago
join lp in db.gp_listing_photo on l.Id equals lp.ListingId
join loc in db.gp_location on l.LocationId equals loc.Id
orderby l.DateCreated ascending
select new HelperListings
{
id = l.Id,
HouseNumber = l.HouseNumber,
ListingPrice = l.ListingPrice,
PhotoUrl = lp.PhotoUrl,
AreaStateCode = loc.AreaStateCode
}
).Distinct().ToList().ToPagedList(page ?? 1, 15);
For Reference : LINQ Select Distinct with Anonymous Types
In linq i am trying to do like this
select * from tbl1 join tbl2 on tbl1.column1= tbl2.column1 and tbl1.column2 = tbl2.column2
how can i write the above query in Linq.... i tried like this but giving error
var sasi = from table1 in dtFetch.AsEnumerable()
join table2 in dssap.AsEnumerable()
on new {
table1.Field<string >["SAPQuotationNo"],
table1.Field<string >["Invoiceno"]}
equals new {
table2.Field<string>["SAPQuotationNo"],
table2.Field <string>["Invoiceno"]
}
Use anonymous types
give the properties names
select something
use DataRow.Field as method with round brackets
var sasi = from table1 in dtFetch.AsEnumerable()
join table2 in dssap.AsEnumerable()
on new
{
SAPQuotationNo = table1.Field<string>("SAPQuotationN"),
Invoiceno = table1.Field<string>("Invoiceno")
} equals new
{
SAPQuotationNo = table2.Field<string>("SAPQuotationNo"),
Invoiceno = table2.Field<string>("Invoiceno")
}
select table1;
You can try something like this:
from A in context.A
join B in context.B on new { id = B.ID,//..., type = A.ID,//...}
This is the hint, you can explore.
I am trying to select from multiple tables in an entity model. But there are two columns I would like to select and it's just not working out. The LINQ statement I have is:
var searchResult = from i in _imEntities.Issues
join dept in _imEntities.Departments
on i.Issued_to_dept equals dept.Dept_ID
where i.State == 1
select new {
i.ID_No,
i.Issue_Date,
Raised_By = dept.Dept_Name
.Where(i.Raised_by_Dept == dept.Dept_ID),
Issued_To = dept.Dept_Name
.Where(i.Issued_to_dept == dept.Dept_ID),
Details = i.Details
};
The column names are all correct, but I just can't get the dept_Names into the Raised_By and Issued_To fields. Is there another way to execute this?
Try this:
var query = from i in _imEntities.Issues
join dept_r in _imEntities.Departments
on i.Issued_to_dept equals dept_r.Dept_ID
join dept_i in _imEntities.Departments
on i.Issued_to_dept equals dept_i.Dept_ID
where i.State == 1
select new {
i.ID_No,
i.Issue_Date,
Raised_By = dept_r.Dept_Name,
Issued_To = dept_i.Dept_Name,
Details = i.Details
};
It's not clear what you are trying to achieve. But you definitely trying to apply where filter on single name string (also predicate syntax is not correct). Here is query which conditionally returns Dept_Name in Raised_By and Issued_To properties:
var query = from i in _imEntities.Issues
join dept in _imEntities.Departments
on i.Issued_to_dept equals dept.Dept_ID
where i.State == 1
select new {
i.ID_No,
i.Issue_Date,
Raised_By = (i.Raised_by_Dept == dept.Dept_ID) ? dept.Dept_Name : null,
Issued_To = (i.Issued_to_dept == dept.Dept_ID) ? dept.Dept_Name : null,
Details = i.Details
};
I need to write Join statment after writing query in linq
example :
var Query = (from Tab in Db.Employees
select Tab)
as i have some cases to perform join operation so
i need to do it on this Query Query.Join(Join with another Table like Department); I need the Syntax
if (DeptID != -1){ Query.Join(Join with table Department where FkDeptID = DeptID); }
Consider the usage of join in the LINQ 'query syntax':
from t1 in db.Table1
join t2 in db.Table2 on t1.field equals t2.field
select new { t1.field2, t2.field3}
Something like this?
var results = (from q in Query
join m in myList on q.SomeID = m.SomeID
select unknown);
Try using this query:
var Query =
from e in Db.Employees
join d in Db.Departments on e.FkDeptID equals d.DeptID into departments
select new
{
Employee = e,
Department = departments.SingleOrDefault(),
};
This works assuming that when e.FkDeptID == -1 that there is no record in the Departments table and in that case Department would be assigned null.
You should never have more than one department for an employee so I've used SingleOrDefault rather than FirstOrDefault.
I have a query that has the following
var myvar = from table in MyDataModel
where.....
select new MyModel
{
modelvar1 = ...,
modelvar2 = (from..... into anothervar)
}
What I want to do is have modelvar2 be a join between the result I currently get from anothervar with another table in MyDataModel.
Thanks
The parenthesis looks more like a subquery than a join. This is how you do a join.
Example tables from the AdventureWorks database.
using (DataClasses1DataContext context = new DataClasses1DataContext())
{
// If you have foreign keys correctly in your database you can
// join implicitly with the "dot" notation.
var myvar = from prod in context.Products
where prod.ListPrice < 10
select new
{
Name = prod.Name,
Category = prod.ProductSubcategory.ProductCategory.Name,
};
// If you don't have foreign keys you need to express the join
// explicitly like this
var myvar2 = from prod in context.Products
join prodSubCategory in context.ProductSubcategories
on prod.ProductSubcategoryID equals prodSubCategory.ProductSubcategoryID
join prodCategory in context.ProductCategories
on prodSubCategory.ProductCategoryID equals prodCategory.ProductCategoryID
where prod.ListPrice < 10
select new
{
Name = prod.Name,
Category = prodCategory.Name,
};
// If you REALLY want to do a subquery, this is how to do that
var myvar3 = from prod in context.Products
where prod.ListPrice < 10
select new
{
Name = prod.Name,
Category = (from prodSubCategory in context.ProductSubcategories
join prodCategory in context.ProductCategories
on prodSubCategory.ProductCategoryID equals prodCategory.ProductCategoryID
select prodCategory.Name).First(),
};
// If you want to get a list from the subquery you can do like this
var myvar4 = from prodCategory in context.ProductCategories
select new
{
Name = prodCategory.Name,
Subcategoreis = (from prodSubCategory in context.ProductSubcategories
where prodSubCategory.ProductCategoryID == prodCategory.ProductCategoryID
select new { prodSubCategory.ProductSubcategoryID, prodSubCategory.Name }).ToList(),
};
}
SELECT [t0].[OrderID], [t0].[CustomerID], [t0].[EmployeeID], [t0].[OrderDate], [t0].[RequiredDate], [t0].[ShippedDate], [t0].[ShipVia], [t0].[Freight], [t0].[ShipName], [t0].[ShipAddress], [t0].[ShipCity], [t0].[ShipRegion], [t0].[ShipPostalCode], [t0].[ShipCountry]
FROM [Orders] AS [t0]
INNER JOIN ([Order Details] AS [t1]
INNER JOIN [Products] AS [t2] ON [t1].[ProductID] = [t2].[ProductID]) ON [t0].[OrderID] = [t1].[OrderID]
can be write as
from o in Orders
join od in (
from od in OrderDetails join p in Products on od.ProductID equals p.ProductID select od)
on o.OrderID equals od.OrderID
select o