I am trying to write a HQL Query which selectes rows from a table based on multiple criteria.
firstName,lastName
the catch is that the query should be flexible to ignore any empty or null values
so
select t from table t where (:firstname = '' or t.firstName = :firstName) AND
(:lastName = '' OR t.lastName = :lastName)
I would have thought this would work? But it doesnt - it never returns any rows? Any ideas what could be wrong here? I am very new to HQL thats why this question.
If I am understanding correctly you want a way to allow the user to search by firstName, lastName or both. So you should be checking if the parameter passed in is empty then don't make it a condition. If they supply all blank parameters it would return the whole table. Try:
select t from table t
where (:firstname IS NULL or t.firstName = :firstName) AND
(:lastName IS NULL OR t.lastName = :lastName)
(:firstname = '' or t.firstName = :firstName)
Your criteria is strange. If :firstname = '' and if a firstname (t.firstName) is equal '' in the database, the criteria t.firstName = :firstName is good ('' = '')
You don't need :firstname = ''
But If you want to check null value, you need to do:
t.firstName IS NULL or t.firstName = :firstname
What happens if you run following hql with firstname parameter set to empty string?
select t from table t where (:firstname = '')
and following with firstname parameter set to null:
select t from table t where (:firstname is null)
If any of the above returns the whole table then the HQLs named parameter might support what you are trying to do.
Otherwise you must use different queries for the null parameter cases. You can do this by generating the query dynamically.
I had a similar requirement. I want dynamic but I'm using a tool that just gives an HQL editor, so no Java.
The query below allows for optional parameters. Essentially a pseudo-quazi XOR of sorts . . . wish there was real XOR :/
With this query you just put NA into a param instead of leaving it empty if it is not needed.
Yeah, yeah, yeah . . . it's ugly, but it works and it's easy to alter to any other scenario needing optional params in pure HQL.
SELECT t AS table
FROM Table t
WHERE (t.valSet = :valSet
AND (:category= 'NA' AND :subCategory= 'NA'))
OR (:category != 'NA'
AND (t.valSet = :valSet
AND t.category= :category))
OR (:subCategory != 'NA'
AND (t.valSet = :valSet
AND t.subCategory = :subCategory ))
Related
I am trying to pass a null parameter (:searchQuery) to a native query in Spring Boot, I have tried various different ways but whenever I pass null I get the error
ERROR: operator does not exist: text ~~ bytea
Query
#Query(value = "SELECT count(*) FROM analysis_history ah, analysis_group ag WHERE ah.analysis_group_id = ag.id "
+ "AND ah.creation_date BETWEEN :from AND :to AND ((:searchQuery IS NULL) OR (:searchQuery IS NOT NULL AND ag.name LIKE :searchQuery))", nativeQuery = true)
Long count(#Param("from") Date from, #Param("to") Date to, #Param("searchQuery") String searchQuery);
Can anyone help?
You cannot use like null
SELECT count(*) FROM analysis_history ah, analysis_group ag
WHERE ah.analysis_group_id = ag.id AND ah.creation_date
BETWEEN :from AND :to AND ag.name LIKE :searchQuery
And you pass '%' in the searchQuery when the searchQuery parameter is null? e.g.
repository.count(from, to, searchQuery == null ? "%" : searchQuery);
There is a way to bypass this, but you need access to the EntityManager, and not use the #Query annotation to create that implementation for you.
Long count(Date from,Date to, String searchQuery) {
Number n = em.createNativeQuery("... that query")
.setParameter("from", from, TemporalType.DATE) // assuming that's a Date, and not TimeStamp
.setParameter("to", to, TemporalType.DATE)
.setParameter("searchQuery", "")
.setParameter("searchQuery", searchQuery)
.getSingleResult();
return n.longValue();
}
The first call to .setParameter("searchQuery", "") tells Hibernate what type this is, the next one sets the value.
The problem comes from Postgres doing the typecheck during parsing, and not deferring the error in case the parameter set is a null.
An alternative workaround to the issue posed by #coladict, which is compatible with Query and performs as well as the original would.
SELECT count(*)
FROM analysis_history ah, analysis_group ag
WHERE ah.analysis_group_id = ag.id
AND ah.creation_date BETWEEN :from AND :to
AND (:searchQuery IS NULL OR ag.name LIKE CAST(:searchQuery AS CHARACTER VARYING))
I would like to select Users that has group that has name in a given array or has null group.
This is my attempted query:
#Query("SELECT u FROM User u WHERE (u.group is null OR u.group.name IN :groups)")
Optional<Page<User>> findUsersByKeywordAndGroupIncludingNullGroup(Pageable pageable, #Param("groups") String... groups); but when I run I have an error in SQL syntax.
Therefore, is there a correct way to do this?
Thanks in advance.
Problem with your query is
If you will pass (null or empty) groups, then the resultant query will become
select * from users where users.group is null or users.group in ()
Thus results in Syntax Error near '('
You can do a hack using sPEL
#Query("SELECT U FROM User U " +
"WHERE U.group IS NULL " +
"OR (1=:#{ #groups == null || #groups.size() == 0 ? 1 : 0} OR U.group.name IN :#{#groups})")
List findUserWithoutGroupOrInGroup(#Param("groups") List<String> groups);
Here, I have used a proxy condition
1=:#{ #groups == null || #groups.size() == 0 ? 1 : 0}
Second part of this condition returns 1 if the parameter groups is null or empty, results in condition 1=1 being TRUE and thereby skipping U.group.name IN :#{#groups}
This approach is not a recommended one, and also not scalable.
In my opinion, you should fetch the Users without any Group and Users in given group separately. You can even fire there queries in parallel and control not to fire Users in given group if groups is empty.
please guide, i am able to work with Dynamic Group by , but when selecting non agrigated fields , i get the following error
No property or field 'name' exists in type 'IGrouping`2'
var result311 = (IQueryable)gle1.temptable.Where(a => a.IsAllowed == false && a.Code == "r01");
var result = result311.GroupBy("new (name, FirstAmountOriginal, SecondAccounting)", "it")
.Select("new (it.name,Sum(FirstAmountOriginal) as FirstAmountOriginalx, Sum(SecondAccounting) as SecondAccountingx)");
Please guide
Firstly, you should not group by the fields you want to aggregate and secondly, the grouping creates a grouping Key consisting of the fields you group by (in this case one), so you must address this key afterwards:
var result = result311.GroupBy("new(name)", "it")
.Select(#"new (it.Key.name,
Sum(FirstAmountOriginal) as FirstAmountOriginalx,
Sum(SecondAccounting) as SecondAccountingx)");
I want to query a datatable (dt) and load a 2nd dt with the resultant collection of datarows. Fine - we have the CopyToDataTable() extn mthd for exactly that purpose. However it is constrained to enumerate only over DataRows, which means that I cannot return anything else e.g. a collection of anonymous types. So - how can I modify the values in the datarows?
Eg I have a dt with 3 columns: MyPK, VARCHAR01, VARCHAR02.
Foreach row, if VARCHAR01 or VARCHAR02 has the value "" (i.e. String.Empty) I want to replace that with NULL (which the underlying type allows).
I would do this as follows:
var MyCleanedDatarows =
from o in ds.Tables["dt"].AsEnumerable()
select new {
MyPK = o.Field<string>("MyPK"),
VARCHAR01 = (o.Field<string?>("VARCHAR01") == "" ? NULL : o.Field<string?>("VARCHAR01") ),
VARCHAR02 = (o.Field<string?>("VARCHAR02") == "" ? NULL : o.Field<string?>("VARCHAR02") )
};
...but then I cant use CopyToDataTable() to get back to a dt. I'm thinking I need to modify the datarows before invoking select operator, but I dont know how to achieve that. Any help/thoughts would be v.greatfully recieved.
Thanks in advance,
Tamim.
Take a look at this approach, in MSDN documentation.
http://msdn.microsoft.com/en-us/library/bb669096.aspx
I am looking to optimize my LINQ query because although it works right, the SQL it generates is convoluted and inefficient...
Basically, I am looking to select customers (as CustomerDisplay objects) who ordered the required product (reqdProdId), and are registered with a credit card number (stored as a row in RegisteredCustomer table with a foreign key CustId)
var q = from cust in db.Customers
join regCust in db.RegisteredCustomers on cust.ID equals regCust.CustId
where cust.CustomerProducts.Any(co => co.ProductID == reqdProdId)
where regCust.CreditCardNumber != null && regCust.Authorized == true
select new CustomerDisplay
{
Id = cust.Id,
Name = cust.Person.DisplayName,
RegNumber = cust.RegNumber
};
As an overview, a Customer has a corresponding Person which has the Name; PersonID is a foreign key in Customer table.
If I look at the SQL generated, I see all columns being selected from the Person table. Fyi, DisplayName is an extension method which uses Customer.FirstName and LastName. Any ideas how I can limit the columns from Person?
Secondly, I want to get rid of the Any clause (and use a sub-query) to select all other CustomerIds who have the required ProductID, because it (understandably) generates an Exists clause.
As you may know, LINQ has a known issue with junction tables, so I cannot just do a cust.CustomerProducts.Products.
How can I select all Customers in the junction table with the required ProductID?
Any help/advice is appreciated.
The first step is to start your query from CustomerProducts (as Alex Said):
IQueryable<CustomerDisplay> myCustDisplay =
from custProd in db.CustomerProducts
join regCust in db.RegisteredCustomers
on custProd.Customer.ID equals regCust.CustId
where
custProd.ProductID == reqProdId
&& regCust.CreditCardNumber != null
&& regCust.Authorized == true
select new CustomerDisplay
{
Id = cust.Id,
Name = cust.Person.Name,
RegNumber = cust.RegNumber
};
This will simplify your syntax and hopefully result in a better execution plan.
Next, you should consider creating a foreign key relationship between Customers and RegisteredCustomers. This would result in a query that looked like this:
IQueryable<CustomerDisplay> myCustDisplay =
from custProd in db.CustomerProducts
where
custProd.ProductID == reqProdId
&& custProd.Customer.RegisteredCustomer.CreditCardNumber != null
&& custProd.Customer.RegisteredCustomer.Authorized == true
select new CustomerDisplay
{
Id = cust.Id,
Name = cust.Person.Name,
RegNumber = cust.RegNumber
};
Finally, for optimum speed, have LINQ compile your query at compile time, rather than run time by using a compiled query:
Func<MyDataContext, SearchParameters, IQueryable<CustomerDisplay>>
GetCustWithProd =
System.Data.Linq.CompiledQuery.Compile(
(MyDataContext db, SearchParameters myParams) =>
from custProd in db.CustomerProducts
where
custProd.ProductID == myParams.reqProdId
&& custProd.Customer.RegisteredCustomer.CreditCardNumber != null
&& custProd.Customer.RegisteredCustomer.Authorized == true
select new CustomerDisplay
{
Id = cust.Id,
Name = cust.Person.Name,
RegNumber = cust.RegNumber
};
);
You can call the compiled query like this:
IQueryable<CustomerDisplay> myCustDisplay = GetCustWithProd(db, myParams);
I'd suggest starting your query from the product in question, e.g. something like:
from cp in db.CustomerProducts
join .....
where cp.ProductID == reqdProdID
As you have found, using a property defined as an extension function or in a partial class will require that the entire object is hydrated first and then the select projection is done on the client side because the server has no knowledge of these additional properties. Be glad that your code ran at all. If you were to use the non-mapped value elsewhere in your query (other than in the projection), you would likely see a run-time exception. You can see this if you try to use the Customer.Person.DisplayName property in a Where clause. As you have found, the fix is to do the string concatenation in the projection clause directly.
Lame Duck, I think there is a bug in your code as the cust variable used in your select clause isn't declared elsewhere as a source local variable (in the from clauses).