CriteriaBuilder count aggregated records - jpa

There are two tables:
Contact
id
firstName
accountId
Account
id
name
I need to count the overall number of contacts grouped by account name.
I'm creating a Pageable web service, the total number of records is needed to calculate the total number of pages.
So the SQL will be something like this:
SELECT COUNT(*) FROM (
SELECT COUNT(a.name)
FROM contact c
LEFT JOIN account a ON c.accountId = a.id
GROUP BY a.name
) AS tmp
How to build a query using the CriteriaBuilder?
The following code returns a list of Long values, e.g. [1, 2, 1]
CriteriaBuilder cb = entityManager.getCriteriaBuilder();
CriteriaQuery<Long> cq = cb.createQuery(Long.class);
Root<Contact> from = cq.from(Contact.class);
Join<Contact, Account> accJoin = from.join("account", JoinType.LEFT);
cq.select(cb.count(from));
cq.groupBy(accJoin.get("name"));
System.out.println("count: " + entityManager.createQuery(cq).getResultList());
Obviously, it executes the following SQL:
SELECT COUNT(a.name)
FROM contact c
LEFT JOIN account a ON c.accountId = a.id
GROUP BY a.name
But I need to get the overall count of records returned by the above query.

Related

Sql to LINQ query LINQ Query convert

I have a SQL query I want to write in LINQ
Here is my Query
SELECT DISTINCT *
FROM [IHQDB].[dbo].[Table1] as t1
inner join Table2 as t2 on t2.Table2 =t1.ChangedItemID
inner join Table3 as t3 on t3.Table3 = t1.FromUserID
where (t1.FromUserID=1 And t2.ContentItemID= t1.ChangedItemID)
OR (t2.LastModifiedBy=1 or t2.CreatedBy=1 )
Hi now its working fine but My query little bit different on place of 1 I need my userID on base of their First Name and Last Name from M_User table.
How can I get UserId on Base of First Name + Last Name.
Here is my LINQ CODE For Retrieving User Name
linq4 = from q in context.T_ContentItems
join p in context.M_Users on q.CreatedBy equals p.UserID
where (advanceKeyword.Contains(p.EmployeeFirstName + " " + p.EmployeeLastName)) select q;
advancechk12 = linq4.ToList();
========================================================================
What I require is that wherever I have written the value "1" (e.g. t2.CreatedBy=1), I need to find the UserID. For simplicity, I am able to get the names of all the filtered users in the advancechk12. How do I retrieve the UserID's of the list of usernames returned in advancechk12
You have to replace below mentioned Linq query with your models name.I just used the same name of the T-Sql.
var t1List = (from t1 in db.Table1
join t2 in db.Table2 on t1.ChangedItemID equals t2.Id
join t3 in db.Table3 on t3.Id equals t1.FromUserID
where ((t1.FromUserID=1 && t2.ContentItemID= t1.ChangedItemID) || (t2.LastModifiedBy=1 or t2.CreatedBy=1))
select t1).Distinct().ToList();

T-SQL filter on external join

Using the schema below, write a query which lists the total value of all sales for customers who bought an item from a sales person with the same middle initial as them. Your query should return a single result.
The quantity and price columns are both ints.
The Sales - Employee link is on EmployeeID - SalesPersonID.
Something like this should work:
select sum(s.Quantity * p.Price) as TotalSales
from Sales s
join Products p on s.ProductID = p.ProductID
join Customers c on s.CustomerID = c.CustomerID
join Empleyees e on s.SalesPersonID = e.EmployeeID
where c.MiddleInitial = e.MiddleInitial

Group by multiple columns in PostgreSQL

I have two queries:
SELECT city, count(id) as num_of_applicants
FROM(
select distinct(students.id), city
FROM STUDENTS INNER JOIN APPLICATIONS ON STUDENTS.ID = APPLICATIONS.STUDENT_ID
WHERE APPLICATIONS.COLLEGE_ID = '28'
) AS derivedTable
GROUP BY city;
SELECT city, count(id) as num_of_accepted_applicants
FROM
(select applications.id, city FROM
STUDENTS INNER JOIN APPLICATIONS ON STUDENTS.ID = APPLICATIONS.STUDENT_ID
WHERE status = 'Accepted' and college_id = '28') as tbl
GROUP BY city
one give the number of applicants for each college and one give the number of accepted applicants in each college, but I want to get a result in on query (instead of) where the result is something like:
city | number_of_applicants | number_of_accepted_applicants
You can simplify (fyi: I didn't understand why you used the derived tables, you could have just put the COUNT and GROUP BY on the inner queries) and combine the queries as this:
SELECT city
, COUNT(*) AS num_of_applicants
, SUM( CASE
WHEN status = 'Accepted' THEN 1
ELSE 0
END
) AS num_of_accepted_applicants
FROM STUDENTS
JOIN APPLICATIONS
ON STUDENTS.ID = APPLICATIONS.STUDENT_ID
WHERE college_id='28'
GROUP BY city;
Another way is to continue with the technique of derived tables. Make each of your queries a derived table and JOIN on the city - but that would not perform as well.

Get Greatest date across multiple columns with entity framework

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.

Using a subquery in an aggregate expression

Instead of this:
SELECT Customer,SUM(OrderPrice) FROM Orders
GROUP BY Customer
How do I get something like above but by producing a COUNT from a subquery.
SELECT Customer,Count(select * from Orders where o.idUser = u.idUser) FROM Orders o
inner join Users u on u.idOrder = o.idOrder
GROUP BY Customer
thx
This should do, I see no need to include Orders in the Topquery:
SELECT u.Customer, (SELECT COUNT(*) FROM Orders o WHERE o.idUser = u.idUser)
FROM Users u