I need help to figure out how the following sql statement can be converted into a linq statement
SELECT distinct tableA.x, tableA.y, tableA.z
FROM tableA inner join
tableB on tableA.id = tableB.id inner join
tableC on tableA.id = tableC.id
WHERE (tableB.columnOne IN (SELECT tableX.columnOne
FROM tableX INNER JOIN
tableY ON tableX.xId = tableY.xId
WHERE (tableY.xId = tableC.xId) )
AND (tableB.columnTwo IN (SELECT tableXx.columnTwo
FROM tableXx INNER JOIN
tableYy ON tableXx.XxId = tableYy.XxId
WHERE tableYy.XxId =tableC.XxId)))
)
I suppose the first thing to point out is that you can do sub queries in LINQ. Within your main Where clause, you could probably create queries for your subqueries, (which would result in IQueryable types) and then use .Any() to predict if there are any matches e.g.
var tableXquery = {my tableX subquery};
var tableXxquery = {my tableXx subquery};
var result = context.tableB.where(b => tableXquery.any(x => x.columnOne == b.columnOne) && xx => tableXxquery.any(xx => xx.columnTwo == b.columnTwo));
I hope you get the idea - I just tend to put queries where they need to be, and let LINQ sort it out!
Related
I have a complex query that I want to use either Query Builder or Eloquent (preferred) but I'm struggling with an inner join.
The inner join needs to be one of either of 2 conditions so if one fails, the other is used.
This is my original query
SELECT DISTINCT tableA.crmid, tableB.*
FROM tableB
INNER JOIN tableA ON tableA.crmid = tableB.customaccountsid
INNER JOIN tableC ON (tableC.relcrmid = tableA.crmid OR tableC.crmid = tableA.crmid)
WHERE tableA.deleted = 0 AND tableC.relcrmid = 123 AND tableC.relation_id = 186
This is my attempt at using Query Builder and I know where the problem lies. It's where I join tableC. I don't know how to use my condition there
DB::table('tableB')
->join('tableA', 'tableA.crmid', '=', 'tableB.customaccountsid')
->join('tableC', function($join) {
$join->on(DB::raw('(tableC.relcrmid = tableA.crmid OR tableC.crmid = tableA.crmid)'));
})
->where('tableA.deleted', 0)
->where('tableC.relcrmid', 3727)
->where('tableC.relation_id', 186)
->select('tableA.crmid', 'tableB.*')
Ant this is the output of the query when i output as SQL
SELECT `tableA`.`crmid`, `tableB`.*
FROM `tableB`
INNER JOIN `tableA` ON `tableA`.`crmid` = `tableB`.`customaccountsid`
INNER JOIN `tableC` ON `tableC`.`relcrmid` = (tableC.relcrmid = tableA.crmid OR tableC.crmid = tableA.crmid)
WHERE `tableA`.`deleted` = ? AND `tableC`.`relcrmid` = ? AND `tableC`.`relation_id` = ?
Just try this:
->join('tableC', function ($join){
$join->on(function($query){
$query->on('tableC.relcrmid', '=', 'tableA.crmid')
->orOn('tableC.crmid', '=', 'tableA.crmid');
});
})
It returns as in your original query:
INNER JOIN tableC ON (tableC.relcrmid = tableA.crmid OR tableC.crmid = tableA.crmid)
Below is my pure SQL query.
SELECT a.*, b.*
FROM a
INNER JOIN b
ON a.id = b.a_id
INNER JOIN (
SELECT a_id, MAX(add_time) AS max_add_time
FROM b
GROUP BY a_id
) m
ON b.a_id = m.a_id AND b.add_time = m.max_add_time
ORDER BY b.add_time DESC
I have the subquery in the second INNER JOIN. Below my active query.
$subQuery = B::find()->select(['a_id', 'MAX(add_time) AS max_add_time'])->groupBy('a_id');
$query = A::find()->innerJoin('b', 'a.id = b.a_id')
->innerJoin('(' .
$subQuery->prepare(Yii::$app->db->queryBuilder)
->createCommand()
->rawSql
. ') m', 'b.a_id = m.a_id AND a.add_time = m.max_add_time ')
->orderBy('b.add_time DESC');
It works fine, but I do not like the way I use the subquery in the second INNER JOIN. What I want to approach with this query is to select the left table inner join with right table, group by a_id and order by the add_time (DESC) of the right table. How should I better use the subquery in the second INNER JOIN?
The snippet below is untested but it should be something like that. If you read the docs (at http://www.yiiframework.com/doc-2.0/yii-db-query.html#innerJoin()-detail) you can see an array with a subquery is also valid input, with the key being the alias.
$subQuery = B::find()
->select(['a_id', 'MAX(add_time) AS max_add_time'])
->groupBy('a_id');
$query = A::find()
->innerJoin('b', 'a.id = b.a_id')
->innerJoin(['m' => $subQuery], 'b.a_id = m.a_id AND a.add_time = m.max_add_time')
->orderBy('b.add_time DESC');
Having created the join, if you need to use any of the columns returned by the subQuery, you need to add properties to the Yii2 model class, e.g.
$subQuery = FinancialTransaction::find()
->select( new \yii\db\Expression( 'SUM(amount) as owing') )
->addSelect('booking_id')
->groupBy('booking_id');
$query = $query
->addSelect(['b.*', 'owing'])
->leftJoin(['ft' => $subQuery], 'b.booking_display_id = ft.booking_id');
To access "owing" the model has to have the property (PHPdoc optional):
/**
* #var float
*/
public $owing=0;
I am trying to write the LINQ statement for the following OUTER JOIN with COUNT but can't seem to work it out..
My LINQ skills aren't what they should be yet so any pointer would be greatly appreciated.
The SQL statement in question is:
SELECT b.Id,
b.Text,
b.Active,
COUNT(u.BusinessArea_Id)
FROM dbo.[User] AS u RIGHT OUTER JOIN dbo.BusinessArea AS b ON b.Id = u.BusinessArea_Id
GROUP BY b.Id, b.Text, Active
ORDER BY b.Id
I think you can use a linq like this:
var res = (from ba in businessAreas
let count = users.Count(u => u.BusinessArea_Id == ba.Id)
orderby ba.Id
select new {ba.Id, ba.Text, ba.Active, Count = count}
).ToList();
I would like to translate the following SQL into LINQ:
select count(p.ID) as NumPosts,
count(t.Trustee_ID)as TrusteePost,
count(pat.ID)as PatientPost,
count(s.ID) as SpecialistPost
from [dbo].[Posts] as p
left join [dbo].[Trusteehips] as t
on p.Autor_ID = t.Trustee_ID
left join [dbo].[Patients] as pat
on p.Autor_ID = pat.ID
left join [dbo].[Specialists] as s
on p.Autor_ID = s.ID
where p.Deleted = 0
I I've tried this:
var res = from p in context.Posts
join t in context.Trusteeships
on p.Autor.ID equals t.Trustee.ID into tGroup
join pat in context.Patients
on p.Autor.ID equals pat.ID into patGroup
join s in context.Specialists
on p.Autor.ID equals s.ID into sGroup
select new NumUserPosts
{
//CountAllPosts = ?
TrusteePost = tGroup.Count(),
PatientPost = patGroup.Count(),
SpecialistPost = sGroup.Count()
};
But result is this:
1 0 0
0 0 1
0 0 1
0 1 0
and etc.
I expect result
TrusteePost PatientPost SpecialistPost
1000 2000 3000
Why when i try to count group return this result?
SQL query is correct. I would like to translate into LINQ.
The query returns 0 or 1 records per joined Trustee, etc. because you outer join by the unique primary key. So a join into (which is a GroupJoin in fluent syntax) produces a group of 0 or 1 records. If you run the generated SQL query and view the raw query result you'd probably understand better what's going on.
The problem is, there is no LINQ equivalent for count(t.Trustee_ID), etc. Therefore it's impossible to do what you want in one query without "hacking".
Hacking it into one query could be done like so:
(from p in context.Posts.Take(1)
select new
{
TrusteePost = context.Posts
.Count(p1 => context.Trusteeships.Any(x => x.ID == p1.Autor.ID)),
PatientPost = context.Posts
.Count(p2 => context.Patients.Any(x => x.ID == p2.Autor.ID)),
SpecialistPost = context.Posts
.Count(p3 => context.Specialists.Any(x => x.ID == p3.Autor.ID))
})
.AsEnumerable()
.Select(x => new NumUserPosts
{
CountAllPosts = x.TrusteePost + x.PatientPost + x.SpecialistPost,
x.TrusteePost,
x.PatientPost,
x.SpecialistPost
}
The SQL query will be much more elaborate than the original SQL (for example, it involves cross joins), but it will probably still perform pretty well. AsEnumerable prevents the second part from being executed as SQL, which would bloat the SQL statement even more. It simply runs in memory.
I consider this a hack because the first part, context.Posts.Take(1) doesn't really have any meaning, it's only there to serve as a wrapper for the three separate queries. It's poor man's query packaging.
It looks like you're doing group joins instead of left outer joins (see this page).
A left outer join looks more like:
var res = from p in context.Posts
join t in context.Trusteeships
on p.Autor.ID equals t.Trustee.ID into tGroup
from tJoin in tGroup.DefaultIfEmpty()
join pat in context.Patients
on p.Autor.ID equals pat.ID into patGroup
from patJoin in patGroup.DefaultIfEmpty()
join s in context.Specialists
on p.Autor.ID equals s.ID into sGroup
from sJoin in sGroup.DefaultIfEmpty()
select ...
Unfortunately, it doesn't seem that Linq can create a query to count elements in each column.
If you don't mind using multiple queries, you could count each separately, for example:
var trusteePost = (from p in context.Posts
join t in context.Trusteeships on p.Autor.ID equals t.Trustee.ID
select t).Count()
I have a nested WHERE IN clause in my SQL, how would this translate to LINQ, bonus points for using lambda expressions. New to all of this.
SELECT EndowmentID
FROM Criteria c
WHERE c.ID IN(
SELECT CriterionID
FROM Filters
WHERE ChoiceID IN(
SELECT ChoiceID
FROM Responses
WHERE ApplicationID = 1
)
)
This query can definitely be improved using joins...
SELECT EndowmentID
FROM
Criteria C
JOIN Filters F ON C.ID = F.CriterionID
JOIN Responses R ON F.ChoiceID = R.ChoiceID
WHERE R.ApplicationID = 1
Depending on the keys of your tables you might have to SELECT DISTINCT
From there you can write a simple LINQ query:
from c in Criteria
join f in Filters on c.ID equals f.CriterionID
join r in Responses on f.ChoiceID equals r.ChoiceID
where r.ApplicationID = 1
select c.EndowmentID
Again, you might have to Distinct() this.
var result =
Criteria.Where(c =>
Filters.Where(f =>
Responses.Where(r => r.ApplicationId == 1).Select(r => r.ChoiceId)
.Contains(f.ChoiceId)
).Select(f => f.CriterionId)
.Contains(c.Id)
).Select(c => EndowmentId);