I'm using Fluent BQL to join a CreatedByID column to Users, to get the user name (simple example below).
public SelectFrom<GIDesign>
.InnerJoin<CreatedUsers>.On<CreatedUsers.pKID.IsEqual<GIDesign.createdByID>>
.OrderBy<GIDesign.name.Asc>.View GIs;
However, the SQL join condition ends up like this...
INNER JOIN [Users] [CreatedUsers_Users] ON NULL = [GIDesign].[CreatedByID]
AND ( [CreatedUsers_Users].[CompanyID] IN ( 1, 2)
AND 8 = SUBSTRING( [CreatedUsers_Users].[CompanyMask], 1, 1) & 8)
AND [CreatedUsers_Users].[DeletedDatabaseRecord] = 0
The join condition NULL = CreatedByID is of course returning no records. I tried swapping the left and right side of the join and then get this as the first join condition:
INNER JOIN [Users] [CreatedUsers_Users] ON [GIDesign].[CreatedByID] =
AND ...
Notice the missing right side of the equation? What am I missing, or doing wrong?
I was able to solve it myself shortly after I posted this. I removed the PXProjection attributes, added a Serializable attribute, plus removed PK member classes I had added to try to resolve the issue. So one of these changes must have been the key.
Related
So I'm trying to inner join multiple tables in order to bind jsonb with a name. But I'm getting this error.
ERROR: invalid reference to FROM-clause entry for table "mt"
Find the recreational fiddle of the problem below.
SELECT test,jsonb_build_object(
'myData_updated',
json_agg(elems || jsonb_build_object('product_name', po.name))
)
FROM mainTable mt,
jsonb_array_elements(mt.myData) AS heading_elems,
jsonb_array_elements(heading_elems -> 'pItems') AS elems
JOIN products po ON (elems ->> 'pid' )::int = po.pid
INNER JOIN clients client ON client.client_id = mt.client_id
INNER JOIN projects project on project.project_id = mt.project_id
https://dbfiddle.uk/?rdbms=postgres_10&fiddle=63e5b8a49940bb50b5bb7985a947c09e
I have tried removing alias i still get the same error. Quick googling says it is caused because of JOIN & ", delimited FROM" query
The syntax
table,
json_array_elements()
is the shortcut for
table CROSS JOIN LATERAL
json_array_elements()
So with the , syntax you used is an implicit join. After that, with using INNER JOIN you are using an explicit join. The mix is not always working, so replace the implicit syntax with an explicit one and it works.
demo:db<>fiddle
Beside this, the used function json_agg() is an aggregate, so if you want to get other columns like test you have to do a GROUP BY and/or use more aggregate functions on these columns.
right now I am "learning" Postgres SQL. I have 3 tables:
1) User: userId
2) Stack :stackId
3) User_Stack: userId, stackId
Now I want to fetch all stacks belonging to one user, given the userId. I understand I need to use Joins, but thats were I get stuck... I try it like this:
SELECT * FROM "Stack" LEFT OUTER JOIN "User_Stack" ON ('User_Stack.stackId' = 'Stack.stackId') WHERE "userId" = '590855';
Error: The returned data is empty.
PS: Is there any GUI Query builder out there ? Or do you have any other tips how to systematically create queries ?
EDIT: If I change the query to this:
SELECT * FROM "Stack" INNER JOIN "User_Stack" ON (User_Stack.stackId = Stack.stackId) WHERE "userId" = '590855';
I get the following error:
Kernel error: ERROR: missing FROM-clause entry for table "user_stack"
LINE 1: SELECT * FROM "Stack" INNER JOIN "User_Stack" ON (User_Stack...
Your main error is in the join. If you do 'something' = 'other' you're comparing string literals, not getting anything from the database. So this will always return false. You will want to compare table1.field1 = table2.field2
Another thing is the LEFT OUTER JOIN. I'm pretty sure you want an INNER JOIN since you want only fields that exist in the other table.
Also don't use double quotes for fields and table names since then the database will require case sensitivity and usually it's not good to have case sensitive names. You can use them with lowercase names if you need and always create them in lowercase.
Numbers also don't need to be quoted, it will just cause more processing when the system has to convert them from text to numbers.
I'm trying to get an average for a count on a groupBy by joining with a subquery. Don't know if that the right way to go at all but I couldn't anything about subqueries other than the mysema doc.
Scenario:
How many orders per product did a customer do on average?
Meaning: A Customer orders products. So a customer ordered a specific product a number of times (count). What's the average number of orders that customer placed for any product?
Might sound a bit hypothetical, in fact it's just part of a prototype, but it made me wonder, how to get a reference to a custom column created within a subquery with the fancy QueryDSL from Mysema.
In SQL you just give the count column an alias and join using a second ID column. QueryDSL has the "as()" method as well but I have no Idea, how to retrieve that column plus I dont't see how it can join one query with anothers, since query.list() just gets a list but for some reason the join accepts it. Feels wrong...
Here's my code:
JPQLQuery query = createJPQLQuery();
QOrdering qOrdering = QOrdering.ordering;
QProduct qProduct = QProduct.product;
QCustomer qCustomer = QCustomer.customer;
// how many of each product did a customer order?
HibernateSubQuery subQuery = new HibernateSubQuery();
subQuery.from(qOrdering).innerJoin(qOrdering.product,qProduct).innerJoin(qOrdering.customer, qCustomer);
subQuery.groupBy(qCustomer,qProduct).list(qCustomer.id,qProduct.id,qProduct.count());
// get the average number of orders per product for each customer
query.from(qCustomer);
query.innerJoin(subQuery.list(qCustomer.id,qOrdering.count().as("count_orders")));
query.groupBy(qCustomer.id);
return (List<Object[]>) query.list(qCustomer.firstname,subQuery.count_orders.avg());
Again: How do I join with a subquery?
How do I get the aliased "count" column to do more aggregation like avg (is my group right btw?)
Might be that I have some other errors in this, so any help appreciated!
Thanks!
Edit:
That's kind of the native SQL I'd like to see QueryDSL produce:
Select avg(numOrders) as average, cust.lastname from
customer cust
inner join
(select count(o.product_id) as numOrders, c.id as cid, p.name
from ordering o
inner join product p on o.product_id=p.id
inner join customer c on o.customer_id=c.id
group by o.customer_id, o.product_id) as numprods
on cust.id = numprods.cid
group by numprods.cid
order by cust.lastname;
Using subqueries in the join clause is not allowed. in JPQL, subqueries are only allowed in the WHERE and HAVING part. The join method signatures in Querydsl JPA queries are too wide.
As this query needs two levels of grouping, maybe it can't be expressed with JPQL / Querydsl JPA.
I'd suggest to write this query using the Querydsl JPA Native query support.
As Querydsl JPA uses JPQL internally, it is restricted by the expressiveness of JPQL.
I know that this question is old and already has an accepted answer, but judging from this question, it seems to still be troubling guys. See my answer in the same question. The use of JoinFlag in the join() section and Expression.path() is able to achieve left-joining a subquery. Hope this helps someone.
QueryDsl does not support subQuery in join but you can achieve this via following way:
We wanted to achieve the following query:
select A.* from A join (select aid from B group by aid) b on b.aid=A.id;
Map a View or SQL query to JPA entity:
import lombok.Setter;
import org.hibernate.annotations.Subselect;
import org.hibernate.annotations.Synchronize;
import javax.persistence.Entity;
import javax.persistence.Id;
#Entity
#Getter
#Setter
#Subselect("select aid from B group by aid")
#Synchronize("B")
public class BGroupByAid {
#Id
private Integer aId;
}
then use the equivalent QueryDSl entity in the class just like the regular entity:
JPAQuery<QAsset> query = new JPAQuery<>(entityManager);
QBGroupByAid bGroupById = QBGroupByAid.bGroupByAid;
List<A> tupleOfAssets =
query.select(A)
.from(A).innerJoin(bGroupById).on(bGroupById.aId.eq(A.aId))
.fetchResults()
.getResults();
You can also use blazebit which supports also subquery in join. I have try it and it is working. You can create SubQueryExpression f.e like this
SubQueryExpression<Tuple> sp2 = getQueryFactory().select(entity.id,
JPQLNextExpressions.rowNumber().over().partitionBy(entity.folId).orderBy(entity.creationDate.desc()).as(rowNumber))
.from(entity)
.where(Expressions.path(Integer.class, rowNumber).eq(1));
and then just join it like this:
return getBlazeQueryFactory()
.select(entity1, entity)
.from(entity1)
.leftJoin(sp2, entity).on(entity.id.eq(entity1.id)).fetch();
I have put here just simple example. So maybe it doesn't make a perfect sense but maybe can be helpful.
Also don't be confused it will can produce union in the generated select. This is just for naming columns from subquery you can read better explanation about this union here: Blaze-Persistence GROUP BY in LEFT JOIN SUBQUERY with COALESCE in root query
I want to perform a simple join on two tables (BusinessUnit and UserBusinessUnit), so I can get a list of all BusinessUnits allocated to a given user.
The first attempt works, but there's no override of Select which allows me to restrict the columns returned (I get all columns from both tables):
var db = new KensDB();
SqlQuery query = db.Select
.From<BusinessUnit>()
.InnerJoin<UserBusinessUnit>( BusinessUnitTable.IdColumn, UserBusinessUnitTable.BusinessUnitIdColumn )
.Where( BusinessUnitTable.RecordStatusColumn ).IsEqualTo( 1 )
.And( UserBusinessUnitTable.UserIdColumn ).IsEqualTo( userId );
The second attept allows the column name restriction, but the generated sql contains pluralised table names (?)
SqlQuery query = new Select( new string[] { BusinessUnitTable.IdColumn, BusinessUnitTable.NameColumn } )
.From<BusinessUnit>()
.InnerJoin<UserBusinessUnit>( BusinessUnitTable.IdColumn, UserBusinessUnitTable.BusinessUnitIdColumn )
.Where( BusinessUnitTable.RecordStatusColumn ).IsEqualTo( 1 )
.And( UserBusinessUnitTable.UserIdColumn ).IsEqualTo( userId );
Produces...
SELECT [BusinessUnits].[Id], [BusinessUnits].[Name]
FROM [BusinessUnits]
INNER JOIN [UserBusinessUnits]
ON [BusinessUnits].[Id] = [UserBusinessUnits].[BusinessUnitId]
WHERE [BusinessUnits].[RecordStatus] = #0
AND [UserBusinessUnits].[UserId] = #1
So, two questions:
- How do I restrict the columns returned in method 1?
- Why does method 2 pluralise the column names in the generated SQL (and can I get round this?)
I'm using 3.0.0.3...
So far my experience with 3.0.0.3 suggests that this is not possible yet with the query tool, although it is with version 2.
I think the preferred method (so far) with version 3 is to use a linq query with something like:
var busUnits = from b in BusinessUnit.All()
join u in UserBusinessUnit.All() on b.Id equals u.BusinessUnitId
select b;
I ran into the pluralized table names myself, but it was because I'd only re-run one template after making schema changes.
Once I re-ran all the templates, the plural table names went away.
Try re-running all 4 templates and see if that solves it for you.
I am using version 2.1 of SubSonic. I am trying to build to build a relatively simple query where I get a list of Roles for a User using UserId as a parameter. (UserId is a string...)
SubSonic.SqlQuery sel = new SubSonic.Select().From(Data.Tables.Role).InnerJoin(Data.Tables.UserRole, Data.UserRole.Columns.RoleId, Data.Tables.Role, Data.Role.Columns.Id).InnerJoin(Data.Tables.User, Data.User.Columns.Id, Data.Tables.UserRole, Data.UserRole.Columns.UserId).Where("[dbo].[User].[Id]").IsEqualTo(userId);
this generates the query
SELECT [dbo].[Role].[Id], [dbo].[Role].[PID], [dbo].[Role].[Name]
FROM [dbo].[Role]
INNER JOIN [dbo].[UserRole] ON [dbo].[Role].[Id] = [dbo].[UserRole].[RoleId]
INNER JOIN [dbo].[User] ON [dbo].[UserRole].[UserId] = [dbo].[User].[Id]
WHERE [dbo].[User].[Id] = #[dbo].[User].[Id]0
which fails. If I replace the Where with .Where(Data.User.Columns.Id) this generates the query
SELECT [dbo].[Role].[Id], [dbo].[Role].[PID], [dbo].[Role].[Name]
FROM [dbo].[Role]
INNER JOIN [dbo].[UserRole] ON [dbo].[Role].[Id] = [dbo].[UserRole].[RoleId]
INNER JOIN [dbo].[User] ON [dbo].[UserRole].[UserId] = [dbo].[User].[Id]
WHERE [dbo].[Role].[Id] = #Id0
which uses the Role table in the Where clause instead of the User table.
Is this a bug, or am I doing something incorrectly? What would be the correct way to do this? Thanks.
This is fixed in version 2.2 - I would suggest upgrading.