I have three entities: Group, Activity, and Comment. Each entity is represented in the db as a table. A Group has many Activities, and an Activity has many comments. Each entity has a CreatedDate field. I need to query for all groups + the CreatedDate of the most recent entity created on that Group's object graph.
I've constructed a sql query that gives me what I need, but I'm not sure how to do this in entity framework. Specifically this line: (SELECT MAX(X)
FROM (VALUES (g.CreatedDate), (a.CreatedDate), (c.CreatedDate)) Thanks in advance for your help. Here's the full query:
WITH GroupWithLastActivityDate AS (
SELECT DISTINCT
g.Id
,g.GroupName
,g.GroupDescription
,g.CreatedDate
,g.ApartmentComplexId
,(SELECT MAX(X)
FROM (VALUES (g.CreatedDate), (a.CreatedDate), (c.CreatedDate)) AS AllDates(X)) AS LastActivityDate
FROM Groups g
LEFT OUTER JOIN Activities a
on g.Id = a.GroupId
LEFT OUTER JOIN Comments c
on a.Id = c.ActivityId
WHERE g.IsActive = 1
)
SELECT
GroupId = g.Id
,g.GroupName
,g.GroupDescription
,g.ApartmentComplexId
,NumberOfActivities = COUNT(DISTINCT a.Id)
,g.CreatedDate
,LastActivityDate = Max(g.LastActivityDate)
FROM GroupWithLastActivityDate g
INNER JOIN Activities a
on g.Id = a.GroupId
WHERE a.IsActive = 1
GROUP BY g.Id
,g.GroupName
,g.GroupDescription
,g.CreatedDate
,g.ApartmentComplexId
I should add that for now I've constructed a view with this query (plus some other stuff) which I'm querying with a SqlQuery.
Related
I have a requirement to pick up data that is in more than one place and I have some form of recognition if using the coalesce function. Basically I am looking to coalesce the join itself but looking online its seems as if i can only do this on the fields.
So we have a Products and Suppliers table, we also have these as a temp table so in total 4 tables (products, tempproducts, suppliers, tempsuppliers). In the suppliers and products table is where we store our products and suppliers and their temptables we store any new suppliers/products. We also have a tempsupplierproduct which joins new suppliers to new products. However we can end in a situation where a new supplier has an existing product so the new supplier will be in the tempsuppliers table and its product is in the products table NOT the tempproducts as it is not new, we will also have a new tempsupplierproduct to join the two up.
So i want a query which looks in the tempsupplierproducts table and then gets basic information about the supplier and products. To do this i am using a coalesce.
SELECT DISTINCT SP.*, COALESCE(P.Product, PD.Product) 'Product', COALESCE(S.Supplier, SU.Supplier) 'Supplier'
FROM tempsupplierproduct SP
LEFT JOIN tempProduct P ON SP.ProductCode = P.Code
LEFT JOIN Products PD ON SP.ProductCode = PD.Code
LEFT JOIN tempSupplier S ON SP.SupplierCode = S.Code
LEFT JOIN Suppliers SU ON SP.SupplierCode = SU.Code
Now while this works, something at the back of my head tells me it is not entirely right, ideally i want if data is not in table A then join to table B. I have seen maybe coalescing inside the join itself but I am unsure how to do this
LEFT JOIN Suppliers Su ON SP.SupplierCode = COALESCE(S.Code, SU.Code)
maybe away, but I am confused by this, all it is saying is use code in temptable if not there then use supplier code. So what would this mean if we have a code in the temptable, will this try to join on it, if so then this is incorrect also.
Any help is appreciated
You can union the two suppliers tables together and then join them in one go like this. I'm assuming that there are no duplicates between the two tables in this case but with a bit of extra work that could be resolved as well.
WITH AllSuppliers AS
(
SELECT Code, Supplier FROM Suppliers
UNION ALL
SELECT Code, Supplier FROM tempSupplier
)
SELECT DISTINCT SP.*, COALESCE(P.Product, PD.Product) 'Product', S.Supplier
FROM tempsupplierproduct SP
LEFT JOIN tempProduct P ON SP.ProductCode = P.Code
LEFT JOIN Products PD ON SP.ProductCode = PD.Code
LEFT JOIN AllSuppliers S ON SP.SupplierCode = S.Code
If you need to handle duplicates in the two suppliers tables then an approach like this should work, essentially we rank the duplicates and then pick the highest ranked result. For two tables you could use a full outer join between the two but this approach will scale to any number of tables.
WITH AllSuppliers AS
(
SELECT Code, Supplier, 1 AS TablePriority FROM Suppliers
UNION ALL
SELECT Code, Supplier, 2 AS TablePriority FROM tempSupplier
),
SuppliersRanked AS
(
SELECT Code, Supplier,
ROW_NUMBER() OVER (PARTITION BY Code ORDER BY TablePriority) AS RowPriority
FROM AllSuppliers
)
SELECT DISTINCT SP.*, COALESCE(P.Product, PD.Product) 'Product', S.Supplier
FROM tempsupplierproduct SP
LEFT JOIN tempProduct P ON SP.ProductCode = P.Code
LEFT JOIN Products PD ON SP.ProductCode = PD.Code
LEFT JOIN SuppliersRanked S ON SP.SupplierCode = S.Code
AND RowPriority = 1
You can absolutely join on a coalesced field. Here is a snippet from one of my production views:
LEFT JOIN [Portal].tblHelpdeskresource supplier ON PO.fld_str_SupplierID = supplier.fld_str_SupplierID
-- Job type a
LEFT JOIN [Portal].tblHelpDeskFault HDF ON PO.fld_int_HelpdeskFaultID = HDF.fld_int_ID
-- Job Type b
LEFT JOIN [Portal].tblProjectHeader PH ON PO.fld_int_ProjectHeaderID = PH.fld_int_ID
LEFT JOIN [Portal].tblPPMScheduleLine PSL ON PH.fld_int_PPMScheduleRef = PSL.fld_int_ID
-- Managers (used to be separate for a & b type, now converged)
LEFT JOIN [Portal].uvw_HelpDeskSiteManagers PSM ON COALESCE(PSL.fld_int_StoreID,HDF.fld_int_StoreID) = PSM.PortalSiteId
LEFT JOIN [Portal].tblHelpdeskResource PHDR ON PSM.PortalResourceId = PHDR.fld_int_ID
SELECT count(d.*)
FROM (
SELECT s.id
,avg(e.marks)
FROM Student s
INNER JOIN Exam e ON s.id = e.student_id
GROUP BY s.id
) d
How to represent this for JPA Criteria query to get no of records
Looks this is not possible in Criteria Query going ahead with Database view for same
I am trying to wrap my head around sub-queries (correlated). Although the book explains (MS SQL Server 2012) it I'm still a little confused. Using three tables, Orders, Products and OrderDetails I want to find the sum of all products that were shipped to USA. I came up with the following query but do not quite understand how I got there except the correlation is referencing the 'where' in the outer query. Can someone correct my work and offer better explanation than book?
SELECT p.productid, p.productname, SUM(qty * od.unitprice) AS TotalAmount
FROM Production.Products AS p
JOIN Sales.OrderDetails AS od
ON p.productid = od.productid
WHERE N'USA' IN
(SELECT o.shipcountry
FROM Sales.Orders AS o
JOIN Sales.OrderDetails AS od
ON o.orderid = od.orderid
WHERE shipcountry = N'USA')
GROUP BY p.productid, p.productname;
SELECT
p.ProductID
, p.ProductName
, SUM(qty * od.UnitPrice) as [Total_Amount]
FROM
Production.Products productid
JOIN Sales.OrderDetails as od on p.productid = od.product
JOIN SalesOrders as o on o.OrderID = od.OrderID
WHERE
o.Shipcountry in ('USA')
Group BY
p.ProductID,
P.ProductName
The following should work - you technically dont require the sub query. Will only bog down the query.
I have a difficulty dealing with a SQL query. I use PostgreSQL.
The query says: Show the customers that have done at least an order that contains products from 3 different categories. The result will be 2 columns, CustomerID, and the amount of orders. I have written this code but I don't think it's correct.
select SalesOrderHeader.CustomerID,
count(SalesOrderHeader.SalesOrderID) AS amount_of_orders
from SalesOrderHeader
inner join SalesOrderDetail on
(SalesOrderHeader.SalesOrderID=SalesOrderDetail.SalesOrderID)
inner join Product on
(SalesOrderDetail.ProductID=Product.ProductID)
where SalesOrderDetail.SalesOrderDetailID in
(select DISTINCT count(ProductCategoryID)
from Product
group by ProductCategoryID
having count(DISTINCT ProductCategoryID)>=3)
group by SalesOrderHeader.CustomerID;
Here are the database tables needed for the query:
where SalesOrderDetail.SalesOrderDetailID in
(select DISTINCT count(ProductCategoryID)
Is never going to give you a result as an ID (SalesOrderDetailID) will never logically match a COUNT (count(ProductCategoryID)).
This should get you the output I think you want.
SELECT soh.CustomerID, COUNT(soh.SalesOrderID) AS amount_of_orders
FROM SalesOrderHeader soh
INNER JOIN SalesOrderDetail sod ON soh.SalesOrderID = sod.SalesOrderID
INNER JOIN Product p ON sod.ProductID = p.ProductID
HAVING COUNT(DISTINCT p.ProductCategoryID) >= 3
GROUP BY soh.CustomerID
Try this :
select CustomerID,count(*) as amount_of_order from
SalesOrder join
(
select SalesOrderID,count(distinct ProductCategoryID) CategoryCount
from SalesOrderDetail JOIN Product using (ProductId)
group by 1
) CatCount using (SalesOrderId)
group by 1
having bool_or(CategoryCount>=3) -- At least on CategoryCount>=3
I am new to Entity framwork and currently trying hard to get used this programming paradigm. I have this query which i want to write in Entity SQL.
SELECT f.id, f.personName, c.Category, j.busCode, s.description, f.StartDate, (SELECT COUNT(*) FROM Analysis WHERE id = f.id) As numOfAnalysis
FROM forms f
INNER JOIN Jobs j ON f.id = j.id
INNER JOIN category c ON j.categoryid = c.categoryid
INNER JOIN stage s ON f.stageid = s.stageid
WHERE j.busCode NOT IN ('xyz', 'YYY')
ORDER BY startDate
I can get records from two tables but as soon as i add third table using the navigation property, i get error table category is not loaded in the current context. I am using .net 3.5. Keep in mind that EDM V2 doest not have foreign keys and i think the only way to traverse through the table relationship is navigation property.
Any help will be deeply appreciated.
Thanks
Coder74
If you use should be able to mount this Linq query.
I tried to put together, but in the rush and no such test is complicated.
You can use this reference as support: http://code.msdn.microsoft.com/101-LINQ-Samples-3fb9811b
var result = (from f in forms
join j in Jobs on f.id equals j.id
join c in Category on j.categoryid equals c.categoryid
join s in stage on f.stageid equals s.stageid
join a in Analysis on a.id equals f.id
where !(new int[] { 'xyz', 'YYY' }).Contains(j.busCode)
orderby f.StartDate
select {
id =f.id,
personName = f.personName,
Category = c.Category,
busCode = j.busCode,
description = s.description,
StartDate = f.StartDate,
numOfAnalysis = a.Count()
}).ToList()
Julio Spader
W&S Soluções de Internet