I'm building a website for an school and i need a list of users that don't have 2 parents asigned. This would be the SQL query:
SQL
SELECT * FROM users
WHERE user_rol = 4
AND user_id IN
(SELECT parent_user_id FROM user_parents
GROUP BY parent_user_id
HAVING COUNT(parent_user_id) < 2);
I'm trying to use LINQ for the same query but I don't know how to use HAVING with LINQ. This has been my closer try for the moment.
SUB-QUERY FOR IN
List<long> usersWithTwoParentsIds = (from currentStudents in contexto.user_parents
select currentStudents.parent_user_id).ToList<long>();
--HELP! having count(currentStudents.parent_user_id) < 2
QUERY
List<vw_user> userList = (from currentStudents in contexto.vw_user
where !usersWithTwoParentsIds.Contains(currentStudents.user_id)
&& currentStudents.group_id == groupID select currentStudents).ToList<vw_user>()
Can anybody give a clue? Thanks :)
Something like this:
var usersWithTwoParentsIds = (
from userParent in contexto.user_parents
group userParent by userParent.parent_user_id into userParentGroups
where userParentGroups.Count() < 2
select userParentGroups.Key)
.ToList();
Assuming the key relations are proper in your data context:
var dat = Context.Users.Where( u => u.Parents.Count() < 2 );
Related
I am trying to figure out how to get all tasks in this case that two of the fields equal a certain value or they exist in the other table?
Here is the query:
SELECT TASKS.task_id, TASKS.task_title, TASKS.task_description, TASKS.task_assigned_name, TASKS.task_assigned_phone_number, TASKS.task_due_date_time, TASKS.task_category
FROM TASKS
WHERE TASKS.task_complete = 1 AND
(TASKS.task_creator_id = ? OR
TASKS.task_assigned_user_id = ? OR
WHERE EXISTS (SELECT WATCHERS.task_id
FROM WATCHERS
WHERE WATCHERS.task_id = TASK.task_id AND
WATCHERS.watcher_user_id = ?
)
);
This is not returning anything even though I am expecting a result from my db.
You seem to have an error in your syntax. You have too many WHEREs:
SELECT t.task_id, t.task_title, t.task_description, t.task_assigned_name, t.task_assigned_phone_number, t.task_due_date_time, t.task_category
FROM TASKS t
WHERE t.task_complete = 1 AND
(t.task_creator_id = ? OR
t.task_assigned_user_id = ? OR
EXISTS (SELECT 1 -- the return value is immaterial
FROM WATCHERS w
WHERE w.task_id = t.task_id AND
w.watcher_user_id = ?
)
);
The WHERE before EXISTS is not appropriate.
Your query should be returning an error. Be sure to check for errors!
Have you tried using a join?
SELECT TASKS.task_id,
TASKS.task_title,
TASKS.task_description,
TASKS.task_assigned_name,
TASKS.task_assigned_phone_number,
TASKS.task_due_date_time,
TASKS.task_category
FROM TASKS
JOIN WATCHERS on WATCHERS.task_id = TASK.task_id
WHERE TASKS.task_complete = 1 AND
(TASKS.task_creator_id = ? OR
TASKS.task_assigned_user_id = ? OR
WATCHERS.watcher_user_id = ?);
I'm not sure if that's the logic you are looking for.
besides the extra where in your query, looks like you may have an extra closed parenthesis.
This sql matches the result set you posted in your duplicate post that has sample data and result:
SELECT t.task_id, t.task_complete, t.task_creator_id, t.task_assigned_user_Id
FROM tasks t
WHERE t.task_complete = 1 AND
(
t.task_creator_id = 8
OR t.task_assigned_user_id = 8
OR EXISTS
(
SELECT w.task_id
FROM watchers w
WHERE w.task_id = t.task_id
AND w.watcher_user_id = 8
)
)
I am trying to figure out how to get all tasks in this case that two of the fields equal a certain value or they exist in the other table?
Here is the query:
SELECT TASKS.task_id, TASKS.task_title, TASKS.task_description, TASKS.task_assigned_name, TASKS.task_assigned_phone_number, TASKS.task_due_date_time, TASKS.task_category
FROM TASKS
WHERE TASKS.task_complete = 1 AND
(TASKS.task_creator_id = ? OR
TASKS.task_assigned_user_id = ? OR
WHERE EXISTS (SELECT WATCHERS.task_id
FROM WATCHERS
WHERE WATCHERS.task_id = TASK.task_id AND
WATCHERS.watcher_user_id = ?
)
);
This is not returning anything even though I am expecting a result from my db.
You seem to have an error in your syntax. You have too many WHEREs:
SELECT t.task_id, t.task_title, t.task_description, t.task_assigned_name, t.task_assigned_phone_number, t.task_due_date_time, t.task_category
FROM TASKS t
WHERE t.task_complete = 1 AND
(t.task_creator_id = ? OR
t.task_assigned_user_id = ? OR
EXISTS (SELECT 1 -- the return value is immaterial
FROM WATCHERS w
WHERE w.task_id = t.task_id AND
w.watcher_user_id = ?
)
);
The WHERE before EXISTS is not appropriate.
Your query should be returning an error. Be sure to check for errors!
Have you tried using a join?
SELECT TASKS.task_id,
TASKS.task_title,
TASKS.task_description,
TASKS.task_assigned_name,
TASKS.task_assigned_phone_number,
TASKS.task_due_date_time,
TASKS.task_category
FROM TASKS
JOIN WATCHERS on WATCHERS.task_id = TASK.task_id
WHERE TASKS.task_complete = 1 AND
(TASKS.task_creator_id = ? OR
TASKS.task_assigned_user_id = ? OR
WATCHERS.watcher_user_id = ?);
I'm not sure if that's the logic you are looking for.
besides the extra where in your query, looks like you may have an extra closed parenthesis.
This sql matches the result set you posted in your duplicate post that has sample data and result:
SELECT t.task_id, t.task_complete, t.task_creator_id, t.task_assigned_user_Id
FROM tasks t
WHERE t.task_complete = 1 AND
(
t.task_creator_id = 8
OR t.task_assigned_user_id = 8
OR EXISTS
(
SELECT w.task_id
FROM watchers w
WHERE w.task_id = t.task_id
AND w.watcher_user_id = 8
)
)
I'm migrating a project to Laravel 4 and I am stuck with a quite complex query, which I'd like to migrate into a proper Eloquent query.
I have a table that contains chat messages, called chat_messages with a representing Model Chatmessage
The table contains a sender and a receipient column with a user id linking to the users table and User Model.
The query to get a list with all user IDs of all chat partners in raw SQL on the old version of the application is as follows:
$sql_allChatPartners = "SELECT DISTINCT chatPartner
FROM ( SELECT * FROM (
SELECT cm_receipient AS chatPartner, cm_sent_at
FROM chat_messages WHERE cm_sender = '".$me->userID."'
UNION
SELECT cm_sender AS chatPartner, cm_sent_at
FROM chat_messages WHERE cm_receipient = '".$me->userID."'
) whateva ORDER BY whateva.cm_sent_at DESC ) other";
Sorry for naming the "fake" tables whateva and other :-)
Could anyone put me in the right direction to do this with Eloquent Querybuilder?
It is important that I get the list of chatPartner IDs in the correct order, where the last chat message has been exchanged as first chatPartner. And the chatPartner where longest inactivity was in the chat as last entry.
This is what I got so far in my User Model...
public function allopenchats(){
$asSender = Chatmessage::where('sender', $this->id)->select('receipient as chatPartner, created_at');
$asBoth = Chatmessage::where('receipient', $this->id)->select('sender as chatPartner, created_at')
->union($asSender)->orderBy('created_at', 'desc')->get();
}
I renamed the columns cm_receipient to receipient, cm_sender to sender and sent_at to created_at in the new database for the new version
Your help would be very much appreciated!
You sql may change to:
SELECT IF (cm_receipient = '10', cm_sender, IF (cm_sender = '10',cm_receipient, 'no')) AS chatPartner, cm_sent_at
FROM chat_messages
WHERE cm_receipient = '10' OR cm_sender = '10'
GROUP BY chatPartner
HAVING chatPartner != 'no'
order by cm_sent_at DESC
In orm:
Chatmessage::where('sender','=',$this->id)
->orWhere('receipient','=',$this->id)
->select(DB::raw('IF (receipient = '.$this->id.', sender, IF (sender = '.$this->id.',receipient, 'no' )) AS chatPartner'), 'created_at')
->groupBy('chatPartner')
->having('chatPartner', '!=', 'no')
->orderBy('created_at', 'desc')
->get();
Thanks very much to Vitalik_74, I wouldn't have come that far without him.
Here is now the final query, although its not in ORM, but it is working fine and gives me the result I need.
$result = DB::select("SELECT *
FROM (
SELECT IF( receipient = '".$this->id."', sender, IF( sender = '".$this->id."', receipient, 'no' ) ) AS chatPartner, created_at
FROM chatmessages
WHERE receipient = '".$this->id."'
OR sender = '".$this->id."'
HAVING chatPartner != 'no'
ORDER BY created_at DESC
)whateva
GROUP BY whateva.chatPartner
ORDER BY whateva.created_at DESC");
if there is someone out there who can do this query with the Laravel Query Builder, I would be happy to see it. For now I'll leave it like this.
I have the following relationship,
And wanted to know how I can get the team a game winner?
SELECT
m.id_match,
IF((id_home_team = ? AND score_home_team > score_away_team) OR
(id_away_team = ? AND score_home_team < score_away_team), 1, 0) AS won
FROM matches m
JOIN results r ON(r.id_match = m.id_match)
WHERE
id_home_team = ? OR id_away_team = ?
Replace the ? with your team's ID.
In SQL Fiddle.
LINQ gurus, I am looking for help to write a query...
I have a table with Person records, and it has a nullable ParentID column, so it is kind of self-referencing, where each record might have a Parent.
I am looking for unprocessed rows whose parent rows were processed.
This SQL works fine:
SELECT *
FROM Person
where IsProcessed = 0 and
ParentId in
(
select Id from Person
where IsProcessed = 1
)
I tried a number of LINQ queries, but they failed. Now, I'm trying:
var qParent =
from parent in db.Person
where
parent.IsProcessed == true
select parent.ID;
var qChildren = from child in db.Person
where
child.IsProcessed == false
&& child.ParentId.HasValue
select child.ParentId.Value;
var q2 = qChildren.Intersect(qParent);
This yields SQL with a DISTINCT clause, for some reason, and I am baffled why DISTINCT is generated.
My main question is how to write LINQ for the SQL statement above?
Thanks in advance.
Intersect is a set operation - it is meant to return a set of distinct elements from the intersection. It seems reasonable to me that it would use DISTINCT in the SQL. There could be multiple children with the same parent, for example - Intersect should only return that ID once.
Is there any reason you don't want to use a join here?
var query = from parent in db.Person
where parent.IsProcessed
join child in db.Person.Where(child => !child.IsProcessed)
on parent.ID equals child.ParentId.Value
select child;
The query can be translated literally into :
var parentIds = db.Person.Where(x => x.IsProcessed)
.Select(x => x.Id)
.ToList();
var result = db.Person.Where(x => !x.IsProcessed && parentIds.Contains(x => x.Id))
.ToList();