SELECT * FROM tbl_scanxmlreports
WHERE Id_XmlMasterFile = (SELECT id
FROM tbl_uploadfilereport
WHERE ProjectId=194);
Sorry to ask this easy question but i am totally new in LINQ.
Thanks in advance to all.
One solution could be:
var scanXmlReportsByProjectId = (from sxr in tbl_scanxmlreports
join ufr in tbl_uploadfilereport on sxr.Id_XmlMasterFile equals ufr.id
where ufr.ProjectId == 194
select sxr).ToList();
You have to join your both tables and filter it by your ID 194 (with the where). After that just select the result.
Please take a look in Microsoft Docs too. It will be very helpful to create queries.
if i'm correct its something like this:
var x = Id_XmlMasterfile.Where(a => a.ProjectId == 194).Select(id);
var result = tbl_scanxmlreports.Where(b => b.Id_XmlMasterfile == x);
but i guess there are more efficient ways
here is a good way to learn about querying in EF
http://www.entityframeworktutorial.net/Querying-with-EDM.aspx
Related
I am experiencing various things while studying JPA, but I am too unfamiliar with it, so I would like to get some advice.
The parts I got stuck in during my study were grouped into three main categories. Could you please take a look at the code below?
#Repository
public interface TestRepository extends JpaRepository<TestEntity,Long> {
#Query(" SELECT
, A.test1
, A.test2
, B.test1
, B.test2
FROM TEST_TABLE1 A
LEFT JOIN TEST_TABLE2 B
ON A.test_no = B.test_no
WHERE A.test3 = ?1 # Here's the first question
if(VO.test4 is not null) AND B.test4 = ?2") # Here's the second question
List<Object[] # Here's the third question> getTestList(VO);
}
First, is it possible to extract test3 from the VO received when using native sql?
Usually, String test1 is used like this, but I wonder if there is any other way other than this.
Second, if extracting is possible in VO, can you add a query in #QUERY depending on whether Test4 is valued or not?
Thirdly, if I use List<Object[]>, can the result of executing a query that is not in the already created entity (eg, test1 in TEST_TABLE2, which is not in the entity of TEST_TABLE1) can be included?,
First, is it possible to extract test3 from the VO received when using native sql? Usually, String test1 is used like this, but I wonder if there is any other way other than this.
Yes, it is possible.
You must use, eg where :#{[0].test3} is equals vo.test3
[0] is position the first param, past for method annotated with #Query
#Query(value = "SELECT a.test1, a.test2, b.test1, b.test2
FROM test_table1 a
LEFT JOIN test_table2 b ON a.test_no = b.test_no
WHERE a.test3 = :#{[0].test3}", nativeQuery = true)
List<Object[]> getList(VO);
Second, if extracting is possible in VO, can you add a query in #QUERY depending on whether Test4 is valued or not?
You can use a trick eg:
SELECT ... FROM table a
LEFT JOIN table b ON a.id = b.id
WHERE a.test3 = :#{[0].test3}
AND (:#{[0].test4} IS NOT NULL AND b.test4 = :#{[0].test4})
Thirdly, if I use List<Object[]>, can the result of executing a query that is not in the already created entity (eg, test1 in TEST_TABLE2, which is not in the entity of TEST_TABLE1) can be included?
Sorry, but I not understand the third question.
Maybe this tutorial will help you: https://www.baeldung.com/jpa-queries-custom-result-with-aggregation-functions
I have a question on how I can extract data from Moodle based on a parameter thats "greater than" or "less than" a given value.
For instance, I'd like to do something like:
**$record = $DB->get_record_sql('SELECT * FROM {question_attempts} WHERE questionid > ?', array(1));**
How can I achieve this, cause each time that I try this, I get a single record in return, instead of all the rows that meet this certain criteria.
Also, how can I get a query like this to work perfectly?
**$sql = ('SELECT * FROM {question_attempts} qa join {question_attempt_steps} qas on qas.questionattemptid = qa.id');**
In the end, I want to get all the quiz question marks for each user on the system, in each quiz.
Use $DB->get_records_sql() instead of $DB->get_record_sql, if you want more than one record to be returned.
Thanks Davo for the response back then (2016, wow!). I did manage to learn this over time.
Well, here is an example of a proper query for getting results from Moodle DB, using the > or < operators:
$quizid = 100; // just an example param here
$cutoffmark = 40 // anyone above 40% gets a Moodle badge!!
$sql = "SELECT q.name, qg.userid, qg.grade FROM {quiz} q JOIN {quiz_grades} qg ON qg.quiz = q.id WHERE q.id = ? AND qg.grade > ?";
$records = $DB->get_records_sql($sql, [$quizid, $cutoffmark]);
The query will return a record of quiz results with all student IDs and grades, who have a grade of over 40.
I have the following models and relations:
Ads has many-to-many with Cities
Ads has many-to-many with Categories
Now I want to get Ads for a specific City and specific Category. So in SQL I do the following and getting the correct result:
select * from ads
inner join ad_cities on ad_cities.adId = ads.id
inner join ad_categories on ad_categories.adId = ads.id
where ad_cities.cityId = 1525
and ad_categories.categoryId = 6
I know it can be done using DB:table(xxxx)->join->....
But I want to know if the same can be done on the model without taking the DB:table approach.
I tried the following and getting the result, but the query generated doesn't seem to be efficient.
return Category::find(6)
->ads()
->whereHas('cities', function ($query) {
$query->where('cityId', '=', '1525');
})
->where('statusName', '=', 'PUBLISHED')
->orderBy('publishedAt', 'DESC')
->simplePaginate($pageSize);
This generated the following query:
select `ads`.*, `ad_categories`.`categoryId` as `pivot_categoryId`, `ad_categories`.`adId` as `pivot_adId` from `ads` inner join `ad_categories` on `ads`.`id` = `ad_categories`.`adId` where `ad_categories`.`categoryId` = '6' and (select count(*) from `cities` inner join `ad_cities` on `cities`.`id` = `ad_cities`.`cityId` where `ad_cities`.`adId` = `ads`.`id` and `cityId` = '1525') >= 1 and `statusName` = 'PUBLISHED' order by `publishedAt` desc limit 16 offset 0
Appreciate your help.
Thanks,
Velu
I've spent quite some time banging my head against this one in my own projects, and the best I can some up with is this:
return Category::find(6)
->ads()
->join('ad_cities', 'ad_cities.adId', '=', 'ads.id')
->where('ad_cities.cityId', 1525)
->where('statusName', '=', 'PUBLISHED')
->orderBy('publishedAt', 'DESC')
->simplePaginate($pageSize);
It's something, right? It gives you the right SQL and preserves the Eloquent API to some extent. The other thing I've been doing, with queries that I couldn't even shoehorn into this, is using hydrate and hydrateRaw after fetching with raw SQL.
This way, when someday I figure out how to use Eloquent effectively and/or Eloquent matures, the interface between Model and Controller will still be right and I can just replace the SQL with ORM goodness.
Also, let me know if you find a better way.
I have the following SQL query, which I'm struggling to convert to LINQ.
Purpose: Get the top 10 coupons from the table, ordered by the date they expire (i.e. list the ones that are about to expire first) and then randomly choosing one of those for publication.
Notes: Because of the way the database is structured, there maybe duplicate Codes in the Coupon table. Therefore, I am using a GROUP BY to enforce distinction, because I can't use DISTINCT in the sub select query (which I think is correct). The SQL query works.
SELECT TOP 1
c1.*
FROM
Coupon c1
WHERE
Code IN (
SELECT TOP 10
c2.Code
FROM
Coupon c2
WHERE
c2.Published = 0
GROUP BY
c2.Code,
c2.Expires
ORDER BY
c2.Expires
)
ORDER BY NEWID()
Update:
This is as close as I have got, but in two queries:
var result1 = (from c in Coupons
where c.Published == false
orderby c.Expires
group c by new { c.Code, c.Expires } into coupon
select coupon.FirstOrDefault()).Take(10);
var result2 = (from c in result1
orderby Guid.NewGuid()
select c).Take(1);
Here's one possible way:
from c in Coupons
from cs in
((from c in coupons
where c.published == false
select c).Distinct()
).Take(10)
where cs.ID == c.ID
select c
Keep in mind that LINQ creates a strongly-typed data set, so an IN statement has no general equivalent. I understand trying to keep the SQL tight, but LINQ may not be the best answer for this. If you are using MS SQL Server (not SQL Server Compact) you might want to consider doing this as a Stored Procedure.
Using MercurioJ's slightly buggy response, in combination with another SO suggested random row solution my solution was:
var result3 = (from c in _dataContext.Coupons
from cs in
((from c1 in _dataContext.Coupons
where
c1.IsPublished == false
select c1).Distinct()
).Take(10)
where cs.CouponId == c.CouponId
orderby _dataContext.NewId()
select c).Take(1);
Okay I'm new to EF and I'm having issues grasping on filtering results...
I'd like to emulate the ef code to do something like:
select *
from order o
inner join orderdetail d on (o.orderid = d.orderid)
where d.amount > 20.00
just not sure how this would be done in EF (linq to entities syntax)
Your SQL gives multiple results per order if there's multiple details > 20.00. That seems wrong to me. I think you want:
var q = from o in Context.Orders
where o.OrderDetails.Any(d => d.Amount > 20.00)
select o;
I would do it like that:
context.OrderDetails.Where(od => od.Amount > 20).Include("Order").ToList().Select(od => od.Order).Distinct();
We are taking details first, include orders, and take distinct orders.