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
Related
There is an example request in which there are several joins.
SELECT DISTINCT ON(a.id_1) 1, a.name, b.task, c.created_at
FROM a
INNER JOIN b ON a.id_2 = b.id
INNER JOIN c ON a.ID_2 = c.id
WHERE a.deleted_at IS NULL
ORDER BY a.id_1 desc
In this case, the query will work, sorting by unique values of id_1 will take place. But I need to sort by the column a.name. In this case, postresql will swear with the words ERROR: SELECT DISTINCT ON expressions must match initial ORDER BY expressions.
The following query can serve as a solution to the problem:
SELECT *
FROM(
SELECT DISTINCT ON(a.id_1) a.name, b.task, c.created_at
FROM a
INNER JOIN b ON a.id_2 = b.id
INNER JOIN c ON a.ID_2 = c.id
WHERE a.deleted_at IS NULL
)
ORDER_BY a.name desc
But in reality the database is very large and such a query is not optimal. Are there other ways to sort by the selected column while keeping one uniqueness?
I have a working PostgreSQL query, but it is taking a considerable amount of time to execute. I need help optimising it.
I have:
Removed inner queries as much as possible.
Removed the unnecessary data from the query.
Created a with query which gets the required data from the beginning
I need help to optimise this query
with data as (
select
e.id,
e.name,
t.barcode,
tt.variant,
t.cost_cents::decimal / 100 as ticket_cost,
t.fee_cents::decimal / 100 as booking_fee
from
tickets t
inner join events e on t.event_id = e.id
inner join ticket_types tt on t.ticket_type_id = tt.id
where
t.status = 2
and e.source in ('source1', 'source2')
)
select
d.name,
count(distinct d.barcode) as issued,
(select count(distinct d2.barcode) from data d2 where d2.id = d.id and d2.variant is null) as sold,
sum(d.ticket_cost) as ticket_revenue,
sum(d.booking_fee) as booking_fees
from
data d
group by
id,
name
Better to detect slow parts with using EXPLAIN .
It will show cost of all parts
You can speed up joins by creating proper indexes.
Also, remove the subquery
(select count(distinct d2.barcode) from data d2 where d2.id = d.id and d2.variant is null)
from the SELECT clause and add a join to d2 table something like this:
select
d.name,
count(distinct d.barcode) as issued,
count(distinct d2.barcode) as sold,
sum(d.ticket_cost) as ticket_revenue,
sum(d.booking_fee) as booking_fees
from
data d
left join data d2 on (d2.id = d.id and d2.variant is null)
group by
d.id,
d.name
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 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.
I am trying to write the following SQL query as a JPA query. The SQL query works (MySQL database) but I don't know how to translate it. I get a error token right after the first FROM. There are probably other errors here too because I was not able to find any guides on how to do sub-queries in the from part, aliasing and so on.
SQL query
SELECT tbl.* from (
SELECT u.*, COUNT(u.id) AS question_count FROM app_user AS u
INNER JOIN question AS q ON u.id = q.user_id GROUP BY u.id
) AS tbl ORDER BY tbl.question_count DESC LIMIT 10;
JPA query:
SELECT tbl FROM (SELECT u, COUNT(u.id) question_count FROM User u
INNER JOIN u.questions q ON u.id = q.user_id GROUP BY u.id) tbl
ORDER BY tbl.question_count LIMIT 10")
I can't test this with anything right now, but something along the lines of:
final String queryStr = "SELECT u, COUNT(u.id) FROM User u, Questions q WHERE u.id = q.user_id GROUP BY u.id ORDER BY COUNT(u.id) DESC";
Query query = em().createQuery(queryStr);
query.setMaxResults(10);
List<Object[]> results = query.getResultList(); //Index [0] will contain the User-object, [1] will contain Long with result of COUNT(u.id)