I´m trying do something like this :
Select * from A where id in (Select id_a from B)
But in LINQ
db.A().Join(db.B(), a => a.id, b => b.id_a, (a , b) => new { a, b}).....
I can do a JOIN. Is the best way? Or i have another options?.
I´m using Entity Framework
Thanks
From my SQL to LINQ recipe:
For translating SQL to LINQ query comprehension:
Translate subselects as separately declared variables.
Translate IN to .Contains() and NOT IN to !...Contains(), using literal arrays or array variables for constant lists.
SELECT * must be replaced with select range_variable or for joins, an anonymous object containing all the range variables.
So, for your SQL,
var id_aInB = from b in db.B select b.id_a;
var ans = from a in db.A where id_aInB.Contains(a.id) select a;
Using subquery in LINQ lambda
var q = db.A.Where(a=> db.B.Select(b=>b.id_a).toList().Contains(a.Id)).Select(a=>a);
In Linq there are many ways to express that. That SQL can also be expressed in different ways and probably the best is to use an EXISTS query instead, like:
Select * from A
where EXISTS (Select * from B where A.id = B.id_a)
That could be written in Linq as:
db.A.Where( a => db.B.Any( b => a.Id == b.Id_a ) );
Maybe you need this:
var result=db.A.Select(c=>new {c,listId=db.B.Select(s=>s.id_a)}).Where(w=>w.listId.Contains( w.c.id)).Select(c=>c.c);
Or you can use LINQ like this
from a in db.A
let listId = from b in db.B
select b.id_a
where listId.Contains(a.id)
select a
By the way, use LINQPad,you can get the right lamda by LINQ search
How to Convert this sql query to Linq.
select sum(OutstandingAmt)from IvfReceiptDetails where IvfReceiptId IN(select IvfReceiptId from IvfReceipts where PatientId = 'SI-49650')
I think it is easier to translate SQL using query comprehension syntax instead of lambda syntax.
General rules:
Translate inner queries into separate query variables
Translate SQL phrases in LINQ phrase order
Use table aliases as range variables, or if none, create range variables from table names
Translate IN to Contains
Translate SQL functions such as DISTINCT or SUM into function calls on the entire query.
Here is the code:
var IvfReceiptIds = from IvfReceipt in IvfReceipts
where IvfReceipt.PatientId = "SI-49650"
select IvfReceipt.IvfReceiptId;
var OutstandingAmtSum = (from IvfReceiptDetail in IvfReceiptDetails
where IvfReciptIds.Contains(IvfReceiptDetail.IvfReceiptId)
select IvfReceiptDetail.OutstandingAmt).Sum();
Try this, First get all IvfReceiptId in array based on your inner query used in where condition then check contains. Change name of your _context if it's different.
var arrIvfReceiptId = _context.IvfReceiptDetails.Where(p=>p.PatientId == "SI-49650").ToArray();
var sum = (from ird in _context.IvfReceiptDetails.Where(p=> arrIvfReceiptId.Contains(p.IvfReceiptId))
select OutstandingAmt).Sum();
I'd like to get value by the following SQL using Eloquent ORM.
- SQL
SELECT COUNT(*) FROM
(SELECT * FROM abc GROUP BY col1) AS a;
Then I considered the following.
- Code
$sql = Abc::from('abc AS a')->groupBy('col1')->toSql();
$num = Abc::from(\DB::raw($sql))->count();
print $num;
I'm looking for a better solution.
Please tell me simplest solution.
In addition to #delmadord's answer and your comments:
Currently there is no method to create subquery in FROM clause, so you need to manually use raw statement, then, if necessary, you will merge all the bindings:
$sub = Abc::where(..)->groupBy(..); // Eloquent Builder instance
$count = DB::table( DB::raw("({$sub->toSql()}) as sub") )
->mergeBindings($sub->getQuery()) // you need to get underlying Query Builder
->count();
Mind that you need to merge bindings in correct order. If you have other bound clauses, you must put them after mergeBindings:
$count = DB::table( DB::raw("({$sub->toSql()}) as sub") )
// ->where(..) wrong
->mergeBindings($sub->getQuery()) // you need to get underlying Query Builder
// ->where(..) correct
->count();
Laravel v5.6.12 (2018-03-14) added fromSub() and fromRaw() methods to query builder (#23476).
The accepted answer is correct but can be simplified into:
DB::query()->fromSub(function ($query) {
$query->from('abc')->groupBy('col1');
}, 'a')->count();
The above snippet produces the following SQL:
select count(*) as aggregate from (select * from `abc` group by `col1`) as `a`
The solution of #JarekTkaczyk it is exactly what I was looking for. The only thing I miss is how to do it when you are using
DB::table() queries. In this case, this is how I do it:
$other = DB::table( DB::raw("({$sub->toSql()}) as sub") )->select(
'something',
DB::raw('sum( qty ) as qty'),
'foo',
'bar'
);
$other->mergeBindings( $sub );
$other->groupBy('something');
$other->groupBy('foo');
$other->groupBy('bar');
print $other->toSql();
$other->get();
Special atention how to make the mergeBindings without using the getQuery() method
From laravel 5.5 there is a dedicated method for subqueries and you can use it like this:
Abc::selectSub(function($q) {
$q->select('*')->groupBy('col1');
}, 'a')->count('a.*');
or
Abc::selectSub(Abc::select('*')->groupBy('col1'), 'a')->count('a.*');
There are many readable ways to do these kinds of queries at the moment (Laravel 8).
// option 1: DB::table(Closure, alias) for subquery
$count = DB::table(function ($sub) {
$sub->from('abc')
->groupBy('col1');
}, 'a')
->count();
// option 2: DB::table(Builder, alias) for subquery
$sub = DB::table('abc')->groupBy('col1');
$count = DB::table($sub, 'a')->count();
// option 3: DB::query()->from(Closure, alias)
$count = DB::query()
->from(function ($sub) {
$sub->from('abc')
->groupBy('col1')
}, 'a')
->count();
// option 4: DB::query()->from(Builder, alias)
$sub = DB::table('abc')->groupBy('col1');
$count = DB::query()->from($sub, 'a')->count();
For such small subqueries, you could even try fitting them in a single line with PHP 7.4's short closures but this approach can be harder to mantain.
$count = DB::table(fn($sub) => $sub->from('abc')->groupBy('col1'), 'a')->count();
Note that I'm using count() instead of explicitly writing the count(*) statement and using get() or first() for the results (which you can easily do by replacing count() with selectRaw(count(*))->first()).
The reason for this is simple: It returns the number instead of an object with an awkwardly named property (count(*) unless you used an alias in the query)
Which looks better?
// using count() in the builder
echo $count;
// using selectRaw('count(*)')->first() in the builder
echo $count->{'count(*)'};
Correct way described in this answer: https://stackoverflow.com/a/52772444/2519714
Most popular answer at current moment is not totally correct.
This way https://stackoverflow.com/a/24838367/2519714 is not correct in some cases like: sub select has where bindings, then joining table to sub select, then other wheres added to all query. For example query:
select * from (select * from t1 where col1 = ?) join t2 on col1 = col2 and col3 = ? where t2.col4 = ?
To make this query you will write code like:
$subQuery = DB::query()->from('t1')->where('t1.col1', 'val1');
$query = DB::query()->from(DB::raw('('. $subQuery->toSql() . ') AS subquery'))
->mergeBindings($subQuery->getBindings());
$query->join('t2', function(JoinClause $join) {
$join->on('subquery.col1', 't2.col2');
$join->where('t2.col3', 'val3');
})->where('t2.col4', 'val4');
During executing this query, his method $query->getBindings() will return bindings in incorrect order like ['val3', 'val1', 'val4'] in this case instead correct ['val1', 'val3', 'val4'] for raw sql described above.
One more time correct way to do this:
$subQuery = DB::query()->from('t1')->where('t1.col1', 'val1');
$query = DB::query()->fromSub($subQuery, 'subquery');
$query->join('t2', function(JoinClause $join) {
$join->on('subquery.col1', 't2.col2');
$join->where('t2.col3', 'val3');
})->where('t2.col4', 'val4');
Also bindings will be automatically and correctly merged to new query.
I like doing something like this:
Message::select('*')
->from(DB::raw("( SELECT * FROM `messages`
WHERE `to_id` = ".Auth::id()." AND `isseen` = 0
GROUP BY `from_id` asc) as `sub`"))
->count();
It's not very elegant, but it's simple.
This works fine
$q1 = DB::table('tableA')->groupBy('col');
$data = DB::table(DB::raw("({$q1->toSql()}) as sub"))->mergeBindings($q1)->get();
I could not made your code to do the desired query, the AS is an alias only for the table abc, not for the derived table.
Laravel Query Builder does not implicitly support derived table aliases, DB::raw is most likely needed for this.
The most straight solution I could came up with is almost identical to yours, however produces the query as you asked for:
$sql = Abc::groupBy('col1')->toSql();
$count = DB::table(DB::raw("($sql) AS a"))->count();
The produced query is
select count(*) as aggregate from (select * from `abc` group by `col1`) AS a;
->selectRaw('your subquery as somefield')
Deriving off mpskovvang's answer, here is what it would look like using eloquent model. (I tried updating mpskovvang answer to include this, but there's too many edit requests for it.)
$qry = Abc::where('col2', 'value')->groupBy('col1')->selectRaw('1');
$num = Abc::from($qry, 'q1')->count();
print $num;
Produces...
SELECT COUNT(*) as aggregate FROM (SELECT 1 FROM Abc WHERE col2='value' GROUP BY col1) as q1
Can the below query be achieved with LINQ to SQL?
select id,
(select StateName from b_mstates where id=StateIdFk) as [State Name],
CityName
from b_mcities
var result = b_mcities.where(x => b_mstates.where(y => y.id == StateIdFK)
.contains(x.statename)).ToList();
Your question is pretty tough, because your sql wont run(it is malformed and missing logic). this is the jist of what you will need to do.
Assuming you have your associations set up correctly, it should be as simple as
var result = from city in m_bcities
select new {city.id, city.State.StateName, city.CityName}
I have used too much time (days) on this and I really hope someone can help me out.
I found a good article on describing my problem in a generic way so let's stick to it.
I am trying to build this query but NHibernate fails to build the correct sql and returns a sql query exception.
Column vSagsAendring.Id is invalid in the select list because it is not contained in either an aggregate function or the GROUP BY clause. It could not execute the following query:
select
viewsagsae0_.Id as Id155_,
viewsagsae0_.SagId as SagId155_,
viewsagsae0_.JournalNr as JournalNr155_,
viewsagsae0_.LbfNr as LbfNr155_,
viewsagsae0_.OrgNr as OrgNr155_,
viewsagsae0_.OrgNavn as OrgNavn155_,
viewsagsae0_.AfdNavn as AfdNavn155_,
viewsagsae0_.SagsType as SagsType155_,
viewsagsae0_.Status as Status155_,
viewsagsae0_.SagsbehandlerInit as Sagsbeh10_155_,
viewsagsae0_.Dato as Dato155_,
viewsagsae0_.JournalAktionType as Journal12_155_,
viewsagsae0_.Beskrivelse as Beskriv13_155_,
viewsagsae0_.Ekstern as Ekstern155_
from vSagsAendring viewsagsae0_
group by viewsagsae0_.SagId
var query = from p in _session.Query<ViewSagsAendring>()
group p by p.SagId
into grp
select grp.OrderByDescending(g => g.Dato).First();
This is another version also took from the article:
var query = from p in _session.Query<ViewSagsAendring>()
group p by p.SagId
into grp
let maxDato = grp.Max(g => g.Dato)
from p in grp
where p.Dato == maxDato
select p;
It's have been a long journey, but now it's over. I hope that I can help someone else in the same situation by answering my own question.
var aendring = from sagsAendring in _session.Query<ViewSagsAendring>()
where sagsAendring.Dato ==
(
from innersagsAendring in _session.Query<ViewSagsAendring>()
where innersagsAendring.SagId == sagsAendring.SagId
select innersagsAendring.Dato
).Max()
select sagsAendring;
var result = aendring.ToList();
And because you can chain linq statements you can build a linq filter like this
if(Filters.VisInterneAendringer == false)
query = query.Where(x => x.Ekstern == true);
if (Filters.VisKunNyesteAendringer)
{
query = query.Where(sagsAendring => sagsAendring.Dato ==
(
from innerSagsAendring in Session.Query<ViewSagsAendring>() where innerSagsAendring.SagId == sagsAendring.SagId
select innerSagsAendring.Dato
).Max());
}
return query;
Your queries seem legit for LINQ in EntityFramework.
I'm not sure about hibernate, you might try to use QueryOver API instead of Query
http://nhibernate.info/blog/2009/12/17/queryover-in-nh-3-0.html