I have a requirement which is somewhat similar to this. My API supports a filter where there is more than 8 filter parameter. So, I want to create a query dynamically based on the filter parameter passed. I am using CriteriaBuilder to create a dynamic query.
Now, I am able to create dynamic queries successfully but the issue comes when the user wants to sort on an aggregate functions. In my query, I have 4 aggregate (count) function. So to support sorting on these columns, I just use the expression of this aggregate function but what I want is to use the alias of this expression
Repeating the expression in select and order by doesn't seem right to me. So, is there a solution/workaround to the problem. I want to declare the expression alias once and use it in both select and order by clause and if required in my group by clause in future
You probably need to build a custom projection class, you can find a decent and easy one, SQLProjectionWithAliasSupport in https://hibernate.atlassian.net/browse/HHH-2952 (from Sergey Pulyaev)
If then one wants to support also sub criteria, things get more complicate
Related
When filtering in fields on D365, we have the filter option of 'is one of' which is more like SQL's where in clause. I'm trying to perform such filter operation using Odata but can't find the right way. Lambda has an any and all but don't know how to throw in a list to compare against.
Try using the In Function.
?$filter=Microsoft.Dynamics.CRM.In(PropertyName=#p1,PropertyValues=#p2)&#p1='name'&#p2=['value','value']
The full list of filter's.
I am using gorm to interact with a postgres database. I'm trying to ORDER BY a query that uses DISTINCT ON and this question documents how it's not that easy to do that. So I need to end up with a query in the form of
SELECT * FROM (<subquery>) ORDER BY column;
At first glance it looks like I need to use db.QueryExpr() to turn the query I have into an expression and build another query around it. However it doesn't seem gorm has an easy way to directly specify the FROM clause. I tried using db.Model(expr) or db.Table(fmt.Sprint(expr)) but Model seems to be completely ignored and fmt.Sprint(expr) doesn't return exactly what I thought. Expressions contain a few private variables. If I could turn the original query into a completely parsed string then I could use db.Table(query) but I'm not sure if I can generate the query as a string without running it.
If I have a fully built gorm query, how can I wrap it in another query to do the ORDER BY I'm trying to do?
If you want to write raw SQL (including one that has a SQL subquery) that will be executed and the results added to an object using gorm, you can use the .Raw() and .Scan() methods:
query := `
SELECT sub.*
FROM (<subquery>) sub
ORDER BY sub.column;`
db.Raw(query).Scan(&result)
You pass a pointer reference to an object to .Scan() that is structured like the resulting rows, very similarly to how you would use .First(). .Raw() can also have data added to the query using ? in the query and adding the values as comma separated inputs to the function:
query := `
SELECT sub.*
FROM (<subquery>) sub
WHERE
sub.column1 = ?
AND sub.column2 = ?
ORDER BY sub.column;`
db.Raw(query, val1, val2).Scan(&result)
For more information on how to use the SQL builder, .Raw(), and .Scan() take a look at the examples in the documentation: http://gorm.io/advanced.html#sql-builder
I am writing a cypher query in neo4j that merge few seperate queries with'UNION' operator. Now, the final result need to be sorted according to a specific column and I also need to be able to use 'LIMIT' to the final result so that I can fetch based on pagination request.
How to achieve that? adding 'ORDER BY' or 'LIMIT' at the end doesn't seems to work. Can't find a way to wrap the result as temporary set(as in sql queries) either. Any suggestions?
Currently it is not possible to add a ORDER BY or SKIP/LIMIT clause to the global set of UNION.
This is a pending feature request, see https://github.com/neo4j/neo4j/issues/2725
Maybe you can share your query and we can find a way to do it without UNION ?
We're running Solr 3.6 and are trying to apply a conditional sort on the result set. To clarify, the data is a set of bids, and we want to add the option to sort by the current user's bid, so it can't function as a regular sort (as the bid will be different for each user that runs the query).
The documents in the result set include a "CurrentUserId" and "CurrentBid" field, so I think we need something like the following to sort:
sort=((CurrentUserId = 12345) ? CurrentBid : 0) desc
This is just pseudocode, but the idea is that if the currentUserId in Solr matches the user Id (12345 in this example), then sort by CurrentBid, otherwise, just use 0.
It seems like doing a sort by query might be the way to go with achieving this (or at least form part of the solution), using something like the following query:
http://localhost:8080/solr/select/?q=:&sort=query(CurrentUserId:10330 AND CurrentBid:[1 TO *])+desc
This doesn't seem to be working for me though, and results in the following error:
sort param could not be parsed as a query, and is not a field that exists in the index: ...
The Solr documentation indicates that the query function can be used as a sort parameter from Solr 1.4 onwards, so this seems like it should work.
Any advice on how to go about achieving this would be greatly appreciated.
According to the Solr Documentation link you provided,
Any type of subquery is supported through either parameter dereferencing $otherparam or direct specification of the query string in the LocalParams via "v".
So based on the examples and your query, I think one or both of the following should work:
http://localhost:8080/solr/select/?q=:&sort=query($qq)+desc&qq=(CurrentUserId:10330 AND CurrentBid:[1 TO *])
http://localhost:8080/solr/select/?q=:&sort=query({v='CurrentUserId:10330 AND CurrentBid:[1 TO *]'})+desc
I am using dynamic linq on a project but don’t know how to run a particular query based on parameters. The example below shows the dynamic linq used to run 3 separate queries where a user has entered a filter expression or filer and sort expression etc. Without using if statements to check I (which seems incorrect and messy as I could end up with lots of if statements to cover the many different permutations ) I am unsure of how to generate the statements dynamically. Is this possible? I am running this query against Entity Framework.
context.Users.AsQueryable().Where(filterExpression)
context.Users.AsQueryable().Where(filterExpression).OrderBy(sortExpression)
context.Users.AsQueryable()Take(10).Where(filterExpression).OrderBy(sortExpression)
That should be achieved using expression tree only or may be using if..else clause
How to: Use Expression Trees to Build Dynamic Queries (C# and Visual Basic)