It must be that time of year. Totally having a brain fart.
I have two basic iEnumerable objects. Each object has two fields. In the first object I have a field with an ID and then total.
Id Total
1 23
2 16
3 59
...
In the other object it has a ID field and then Fruit Name
ID Fruit
1 Apple
2 Orange
3. Pear
I need to combine these into a new table by the ID so I get a new object with the fields
ID Total Fruit
1 23 Apple
2 16 Orange
3 59 Pear
What's the best way to go about this using LINQ?
Do a join
from o in iEobject
join f in Fruit on o.ID equals f.ID
select new {ID = o.ID, Total = o.Total, Fruit = f.Name }
Related
I have a query like this:
$foos= Foo::orderBy('order_number', 'asc')->limit(10)->orderBy('updated_at', 'desc')->get();
Its ordering the "order_number" by asc. After one order again.
If there is same order number values in query. Example:
What I want is:
1-2-3-2-3-2-1-1-1-2
There are four "number 1", four "number 2", two "number 3"
Is there a chance to order each number bycreated_at, desc?
The result must be:
1-1-1-1-2-2-2-2-3-3
But 1s are ordered by created_at and 2 and 3 are ordered by created_at.
I have one solution but it's not concise: it uses 3 queries.
Edit1:
in my db
id = 1 / order = 1 / name = john / created_at = 2013
id = 2 / order = 2 / name = jack / created_at = 2016
id = 3 / order = 1 / name = jennifer / created_at = 2015
id = 4 / order = 2 / name = janice / created_at = 2014
after the query result must:
john
jennifer
janice
jack
JOHN's order smaller than jack and janice and earlier than Jennifer. (1st place)
JENNIFER's order smaller than smaller than jack and janice but not earlier than JOHN (2nd place)
JANICE's order and JACK's order is not smaller than others but janice's created_at earlier than jack. So jennifer 3rd place. Jack 4th.
There could be a to many orders of course.
First order by id and then order by created_at
OrderModel::orderBy('id')->latest()->get();
Let's say i have a table structure like this :
ID | Name | SCHOOLNAME | CODESCHOOL
1 DARK Kindergarten 123 1
2 DARK Kindergarten 111 1
3 Knight NY University 3
4 Knight LA Senior HS 2
5 JOHN HARVARD 3
so, how to diplay all of the data above into like this :
ID | Name | SCHOOLNAME | CODESCHOOL
1 DARK Kindergarten 123 1
3 Knight NY University 3
5 JOHN HARVARD 3
my purpose is want to display data with the max of codeschool, but when i tried with my query below :
SELECT NAME, SCHOOLNAME, MAX(CODESCHOOL) FROM TABLE GROUP BY NAME, SCHOOLNAME
but the result is just like this :
ID | Name | SCHOOLNAME | CODESCHOOL
1 DARK Kindergarten 123 1
2 DARK Kindergarten 111 1
3 Knight NY University 3
4 Knight LA Senior HS 2
5 JOHN HARVARD 3
maybe it caused by the GROUP BY SCHOOLNAME, when i tried to not select SCHOOLNAME, the data displayed just like what i expected, but i need the SCHOOLNAME field for search condition in my query
hope you guys can help me out of this problem
any help will be appreciated
thanks
Using some wacky joins you can get a functional get max rows per category query.
What you essentially need to do is to join the table to itself and make sure that the joined values only contain the top values for the CODESCHOOL column.
I've also added a :schoolname parameter because you wanted to search by schoolname
Example:
SELECT
A.*
FROM
TABLE1 A
LEFT OUTER JOIN TABLE1 B ON B.NAME = A.NAME
AND B.CODESCHOOL < A.CODESCHOOL
WHERE
B.CODESCHOOL IS NULL AND
(
(A.SCHOOLNAME = :SCHOOLNAME AND :SCHOOLNAME IS NOT NULL) OR
(:SCHOOLNAME IS NULL)
);
this should create this output, note that dark has 2 outputs because it has 2 rows with the same code school which is the max in the dark "category"/name.
ID|NAME |SCHOOLNAME |CODESCHOOL
--| -----|----------------|----------
4|Knight|LA Senior HS | 2
5|JOHN |HARVARD | 3
2|DARK |Kindergarten 111| 1
1|DARK |Kindergarten 123| 1
It's not the most effective query but it should be more than good enough as a starting point.
Sidenote: I've been blatantly stealing this logic for a while from https://www.xaprb.com/blog/2007/03/14/how-to-find-the-max-row-per-group-in-sql-without-subqueries/
I am using an analytical window function ROW_NUMBER().
This will group (or partition) by NAME then select the top 1 CODESCHOOL in DESC order.
Select NAME,
SCHOOLNAME,
CODESCHOOL
From (
Select NAME,
SCHOOLNAME,
CODESCHOOL,
ROW_NUMBER() OVER (PARTITION BY NAME ORDER BY CODESCHOOL DESC) as rn
from myTable)
Where rn = 1;
My Database Table Contain Records Like this:
ID ProductId Occurences
1 1 1
2 2 5
3 3 3
4 4 3
5 5 5
6 6 8
7 7 9
Now i want to get top 4 ProductId with the highest Occurences.
This is my Query:
var data = (from temp in context.Product
orderby temp.Occurences descending
select temp).Take(4).ToList();
Now here as because ProductId 2 and 5 have same occurences and ProductId 3 and 4 also have same occurences then here I am not getting that how to resolve this means which product id should i take as because they are having same occurences.
Basically i am selecting this productid to display this products on my website.i will display those products which are return by this query.
So can anyone please give me some idea like how to resolve this ???
Expected Output:
ID ProductId Occurences
1 7 9
2 6 8
so Now for 3rd position Which ProductId i should select as because both ProductId 2 and 5 have same Occurences and for 4th position which ProductId i should select among 3 and 4 as because they both too have same occurences.
can I suggest you to use group by technique and pick the first one
context.Product.GroupBy(p => p.Occurance)
.Select(grp => grp.FirstOrDefault())
.Take(4)ToList();
Sorry, I have not tested this but it should do the job. You just need to add OrderBy along with it.
i need to be able to get distinct values grouped by FileID and by SentToID
this is what i have now, and it only groups by SentToID, which is missing some records.
var sentByResults = from v in ctx.vEmailSents
where v.TypeDesc.Equals("Request")
group v by v.SentTo_ID into g
select g.OrderByDescending(x => x.DateSent).FirstOrDefault() into lastV
select new
{
ClaimID = lastV.Claim_ID,
SentToID= lastV.SentTo_ID,
};
so if i have 5 records
claim id fileid sentToID
1 15 27
1 16 27
1 15 26
1 15 26
1 15 47
right now i get 3 records back, one for each unique sentToID, but i need to get 4 records back, for each unique ID within each unique fileID
I suspect you just want to group by an anonymous type:
group v by new { v.SentTo_ID, v.FileID }
Also, given that you'll never get any empty groups, you should be able to use First instead of FirstOrDefault.
I have a table containing a list of customers, a second table containing orders placed by my customers and a third table containing the line items for the orders.
I would like to be able to use a Linq query to get the customer name, the number of orders and the total value of all the orders placed by this customer.
Assuming the following data:
[Customers]
CustomerId Name
---------------------
1 Bob Smith
2 Jane Doe
[Orders]
OrderId CustomerId
---------------------
1 1
2 1
3 2
[OrderLineItems]
LineItemId OrderId UnitPrice Quantity
--------------------------------------------
1 1 5 2
2 1 2 3
3 2 10 10
4 2 4 2
5 3 2 5
I would like the following result:
Name OrdersCount TotalValue
--------------------------------------------
Bob Smith 2 124
Jane Doe 1 10
What would be the Linq query to get this result?
If you presume that you have a strongly typed datacontext and a partial class Customer that you are free to add to, I would solve this problem like this:
public partial class Customer {
public int NumberOfOrders {
get { return Orders.Count(); }
}
public int TotalValue {
get { return Orders.OrderLineItems.Sum( o => o.UnitPrice * o.Quantity); }
}
}
YourDataContext db = new YourDataContext();
var query = from c in db.Customers
select new {c.Name, c.NumberOfOrders,
c.TotalValue}
This would project a new anonymous type with the data you requested.