I got a problem with a quiet simple join statement.
There is a table A and another table B. Table A has an idNumber.
Table B has got an number.
Now I want to join this tables on idNumber=number
What I do is:-
A.executeQuery("Select a from A a inner JOIN B b ON a.idNumber=b.number")
Unfortunately, I get an empty list as result but that is wrong.
Anyone has an idea what I am doing wrong?
It seems you are running a sql query. So for running sql query, you need to define which columns you are selecting.
A.executeQuery("Select a.* from A a inner JOIN B b ON a.idNumber=b.number") // don't forget * after a
PS. For hql query I need to know your class structure.
Hibernate Query Language (HQL) is an object-oriented query language, similar to SQL, but instead of operating on tables and columns, HQL works with persistent objects and their properties.
Let's assume class A has an instance of B. Then JOIN query will be as following.
Select a from A a inner JOIN a.B
A has an instance of B. B is in the package a.package.name
I just tried
A.executeQuery("Select a from A a inner JOIN a.package.name.B b where a.idNumber=b.number")
The Problem was that one Table was in an extern Plugin and it was not possible to join them here. I had to do two requests.
Related
I have two tables A and B and I need to select a property from A only. B has a foreign key pointing to A.id(lets say it is called foreignId). I am trying to write HQL equivalent of:
SELECT A.id
FROM A a LEFT JOIN B b ON a.id = b.foreignId
WHERE ...
If I had a foreign key in table A pointing table B, writing to HQL is not an issue:
select A.id
from A a left join a.foreignId b
where ...
Unfortunately, all HQL examples I see online/in stackoverflow are providing an answer to the second case. I need HQL equivalent of the first case.
Note that this question is completely different than asking how can I write simple join queries in HQL, so please be mindful before marking this question as a duplicate. My first question was marked as duplicate with the following question Hibernate HQL Query with outer join which also exactly the same as my second example.
I'm not super familiar with SQL but I know the basics. I was recently trying to replicate some logic form reports to SQL Server 2012. I started with the custom query from Webi (a reporting tool) and was trying to make a view from it in SQL.
Here is what the query look like:
SELECT
dimGlobalSalesAnalysisTbl.globalSalesAnalysisDesc,
dimGlobalShipDestinationCountryTbl.area,
dimGlobalShipDestinationCountryTbl.subarea,
dimGlobalCurrentProductTbl.sbuCodeDesc,
dimGlobalShipDateVw.shipDayOfWeekDesc,
sum(factSalesTblVw.globalSalesValue) AS 'Global Sales Value',
SUM(factSalesTblVw.salesUnitQuantity*GlobalFiles.dimCurrentGTINTbl.unitQty) AS 'Sales Unit Quantity'
FROM
dimGlobalCookCompaniesTbl INNER JOIN factSalesTblVw ON
(dimGlobalCookCompaniesTbl.globalCookCompanyID=factSalesTblVw.globalCookCompanyID)
INNER JOIN dimGlobalHistProductTbl ON (dimGlobalHistProductTbl.globalHistProductID=factSalesTblVw.globalHistProductID)
INNER JOIN dimGlobalCurrentProductTbl ON (dimGlobalHistProductTbl.globalCurrentProductID=dimGlobalCurrentProductTbl.globalCurrentProductID)
INNER JOIN dimGlobalHistShipCustomerTbl ON (factSalesTblVw.globalHistShipCustomerID=dimGlobalHistShipCustomerTbl.globalHistShipCustomerID)
INNER JOIN dimGlobalCurrentShipCustomerTbl ON (dimGlobalHistShipCustomerTbl.shipCustomerID=dimGlobalCurrentShipCustomerTbl.globalCurrentShipCustomerID)
***INNER JOIN dimGlobalCountryTbl dimGlobalShipDestinationCountryTbl ON (dimGlobalCurrentShipCustomerTbl.shipDestCountryDesc=dimGlobalShipDestinationCountryTbl.countryCode)***
INNER JOIN dimGlobalSalesAnalysisTbl ON (factSalesTblVw.globalSalesAnalysisID=dimGlobalSalesAnalysisTbl.globalSalesAnalysisID)
INNER JOIN dimGlobalShipDateVw ON (dimGlobalShipDateVw.shipJulianDate=factSalesTblVw.shipDateID)
INNER JOIN GlobalFiles.dimCurrentGTINTbl ON (GlobalFiles.dimCurrentGTINTbl.curGtinId=factSalesTblVw.GtinID)
WHERE
(
dimGlobalShipDateVw.shipYearNumber IN (DATEPART(yy,GETDATE())-1)
AND
dimGlobalCurrentShipCustomerTbl.shipCustomerNumberDesc
IN ( 'JPC000222-3','CNC000012-1' )
AND
dimGlobalSalesAnalysisTbl.globalSalesAnalysisDesc = 'Return Credits'
)
GROUP BY
dimGlobalShipDateVw.shipDate,
dimGlobalSalesAnalysisTbl.globalSalesAnalysisDesc,
dimGlobalShipDestinationCountryTbl.area,
dimGlobalShipDestinationCountryTbl.subarea,
dimGlobalCurrentProductTbl.sbuCodeDesc,
Upper(dimGlobalCurrentProductTbl.familyCodeDesc),
dimGlobalShipDateVw.shipYearNumber,
dimGlobalShipDateVw.shipDayOfWeekDesc,
dimGlobalCurrentProductTbl.madeByAbbr,
dimGlobalCookCompaniesTbl.companyDesc
This particular query runs on the production system if ran in the relevant database. When trying to make a view of this query in a different database, I precede the objects by [database_name].[schema/dbo] name.
On running the query, I get the error:
Invalid object name 'WWS.dbo.dimGlobalShipDestinationCountryTbl'
I try to find this particular table on the database, but it isn't there, though hovering over the table name in the query give a table definition but no script.
This table is present in an weird looking inner join (6th inner join) syntax like this:
INNER JOIN dimGlobalCountryTbl dimGlobalShipDestinationCountryTbl ON
(dimGlobalCurrentShipCustomerTbl.shipDestCountryDesc=dimGlobalShipDestinationCountryTbl.countryCode)
Two questions:
1. Can someone please explain this query syntax for inner join ?
2. This is pretty stupid but any ideas on how to look into possibly hidden table definitions ?
Two questions: 1. Can someone please explain this query syntax for inner join ?
The inner join in this case is nothing more than a table alias. The creator of the query thought aliasing the table would be easier to understand this name instead of the actual table name, or the same table is referenced twice and one would have to have an alias.
2. This is pretty stupid but any ideas on how to look into possibly hidden table definitions ?
Why? I think you just have a syntax error on your SQL when you added the database_name.schema syntax.
Think of the table alias like a column alias.... but and just like columns, you can omit the 'AS' keyword...
dimGlobalCountryTbl dimGlobalShipDestinationCountryTbl is the same as
dimGlobalCountryTbl AS dimGlobalShipDestinationCountryTbl
Have a requirement where I need to build a dynamic query based on user input and send the count of records from result set.
So there are 6 tables which I needs to make a join Inner for sure and rest table join will be based on user input and this should be performance oriented.
Here is the requirement
select count(A.A1) from table A
INNER JOIN table B on B.B1=A.A1
INNER JOIN table B on C.C1=B.B1
INNER JOIN table D on D.D1=C.C1
INNER JOIN table E on E.E1=D.D1
INNER JOIN table F on F.F1=E.E1
Now if user select some value in UI , then have to execute query as
select count(A.A1) from table A
INNER JOIN table B on B.B1=A.A1
INNER JOIN table B on C.C1=B.B1
INNER JOIN table D on D.D1=C.C1
INNER JOIN table E on E.E1=D.D1
INNER JOIN table F on F.F1=E.E1
INNER JOIN table B on G.G1=F.F1
Where G.Name like '%Germany%'
User can send 1- 5 choices and have to build the query and accordingly and send the result set
So if I add all the joins first and then add where clause as per the choice , then query will be easy and serve the purpose, but if user did not select any query then I am creating unnecessary join for the user choices.
So which will be better way to write having all the joins in advance and then filtering it or on demand join and with filters using dynamic query.
Could be great if someone can provide valuable inputs.
When SQL Server executes a query, there is a first step which is planning the query, i.e. deciding an strategy to get the query result.
If you use "inner joins" you're making it compulsory to include all the tables, becasuse "inner join" means that there must be matching rows on both tables of the join, so the query planner can't dicard any tables.
However, if you change the inner joins by left outer joins, it's not compulsory that there are matching rows on both sides of the join, so the query planner can decide if it includes or not the tables on the right. So, if you use left outer joins, and you don't select, or filter, or do any operation on fields on the right side of the joins, the query planner can discard then when executing the query. That's the easiest way to get rid of your concerns.
On the other hand, if you want to control what tables to inclued or not to include, and create a custom query for each case, you can use several techniques:
making a graph that includes the definition of the table relations, and using some graph manipulation library that allows you to get the necessary tables from the graph.I did this one, but is quite hard to achieve if you don't have experience with graps.
using Entity Framework. You must build a simple model including all the tables. And then, to run each query, you can programmatically build the query in LINQ, and EF will take care to generate and execute the SQL query for you.
I have the following issue and I would really appreciate your help:
I have all my filtering done through the HQL and one of the filters is a left outer join which must be a sub-select. So my thinking here is that I can create a dummy business object which I would like to populate (with an SP if possible) with data and use it in my left join.
Now how can I do that and still have all of the logic in 1 HQL query?
I guess the biggest issue for me is understanding how can I have this BO (not actually mapped to a table etc.) be used in a query where all the other BOs are mapped to tables etc.
I am trying to avoid doing any filtering in the actual C# code.
Thanks!
Example:
Entity A - mapped to table A
Entity B - mapped to table B
Entity C - mapped to table C
Entity D - not mapped to table - coming from SQL query or SP
HQL:
from A pbo
inner join B.EntityType etype
inner join C.EntityAddressList eadr
left join D.Level lvl
You cannot join to arbitrary SQL in HQL. So I don't think what you're trying to do is possible. You'll likely either have to map whatever D is, or write your query in SQL using Session.CreateSQLQuery(). You can still specify any entities that come back. See this article for reference. http://www.nhforge.org/doc/nh/en/index.html#d0e10274
Is there a way of joining results from 2 tables without using JOIN or SELECT from more than one table? The reason being the database im working with requires queries that only contain SELECT, FROM, and WHERE clauses containing only one distinct table. I do, however, need information from other tables for the project i'm working on.
More info: the querier returns the query results in a .csv format, is there something we can manipulate there?
Pick a programming language. Any language will do. Run one query, and get the results. Run another query, get the results. Use the programming language to combine the results.
Seriously. You are asking how to join data from a database that doesn't support joins. If the database doesn't support it, you're going to have to do it externally.
select a.*, b.* from tablea a, tableb b
You can do it either by Using JOIN or SELECT. You have to use one of it. By Join you must be knowing. I am writing an example for without using JOIN and just using SELECT, to join two tables.
SELECT * from Table1, Table2 where Table1.common_attribute = Table2.common_attribute;