How to I write this in linq?
//The store with the most occurrence
SELECT TOP 1 [StoreName], COUNT(*)
FROM [Xpenses]
GROUP BY [StoreName]
ORDER BY COUNT(*) DESC
//The store where the user spent the most overall
SELECT TOP 1 [StoreName], SUM([Price])
FROM [Xpenses]
GROUP BY [StoreName]
ORDER BY COUNT(*) DESC
Thanks for helping
You could do this:
//First create part of your query you can reuse
var query=Xpenses.GroupBy(x=>x.StoreName);
var MostOccurrence=query.Select(g=>new {Store=g.Key,Count= g.Count()})
.OrderByDescending(r=r.Count).FirstOrDefault();
var MostOverall=query.Select(g=>new {Store=g.Key,Sum= g.Sum(f=>f.Price)})
.OrderByDescending(r=r.Sum).FirstOrDefault();
Related
Hello I'am very new to writing SQL and I am trying to find the appropriate way to use TOP in Oracle SQl 9:
My example:
select * from example e, test t
where e.id = t.id
and country = 'USA'
order by state ASC;
What I am trying to do is take the bottom 20 % of my query but I know you cannot use TOP. After researching I still have not found an applicable answer. I know you have to first order them but am unsure of how to then take the bottom 20%(which would be TOP since the order is ASC)
In general (like if you want the top or bottom 17.2% of the rows) you can use row_number() and count() (analytic functions) to get the result.
20% is easier - you are looking for the top (or bottom) quintile. For this, you can use the ntile() function, like so:
select [column_names]
from (
select e.*, t.*, ntile(5) over (order by state) as nt
from ..... etc
)
where nt = 1;
The subquery is your query. The column_names in the outer query are whatever you actually need; you could also use select * but that will show the ntile too (which will be 1 in all rows).
If sorting something in ASCending order gives us the top set then surely sorting in DESCending order can give us the bottom set.
This solution uses the function NTILE() to divide the records into five buckets. The first bucket is the set we want (because sorted in descending order). Sorting in ascending order and taking the fifth quintile would have the same outcome.
select * from (
select e.*
, t.*
, ntile(5) over (order by state desc) nt
from example e, test t
where e.id = t.id
and country = 'USA'
)
where nt = 1
order by state desc
/
You don't say what your sort criteria are, so I've guessed.
I'm sorry for my strange title, but I don't know what exactly I'm looking for. The task is quite simple. I have the table of competitions. Another table groups. In every group there are several contestants. In the last table are stored the results of contestants. The task is to get the first three of the contestants of every group.
So I have to loop through the groups, get the first three contestants (according to achieved points) of every group and append them into some variable.
Here is the pseudocode:
CREATE OR REPLACE PROCEDURE get_first_three_of_all(contestants OUT SOME_TYPE) AS
CURSOR groups SELECT...
BEGIN
FOR group IN groups LOOP
APPEND(contestants, get_first_three_of_one_group(group.id))
END LOOP;
END;
I have no idea, how to solve this task. I even don't know what should I look for. Would you be so kind and help me, please? Thanks.
Edited: simplified structure of my tables:
Competition: competition_id
Contestant: contestant_id
GroupContestant: contestant_group_id, competition_d, group_number, contestant_id
Result: contestant_group_id, juror, points
Select to get data of one group (group number YYY) is here:
SELECT * FROM (
SELECT res.contestant_group_id, SUM(res.points) AS points
FROM Result res
WHERE res.couple_group_id IN (SELECT couple_group_id
FROM GroupContestant
WHERE competition_id = XXX
AND group_number = YYY)
GROUP BY res.contestant_group_id
ORDER BY points DESC
)
WHERE ROWNUM <= 3;
Analytic functions to the rescue. To select top 3 results for each group, each competition:
SELECT * FROM (
SELECT grp.competition_id, grp.group_number, res.contestant_group_id, res.points,
row_number() over (partition by grp.competition_id, grp.group_number
order by res.points desc) rn
FROM (SELECT contestant_group_id, SUM(points) AS points
FROM Result
GROUP BY contestant_group_id) res
JOIN GroupContestant grp ON (grp.contestant_group_id = res.contestant_group_id)
)
WHERE rn <= 3;
Pay attention to how you resolve ties (consider using rank or dense_rank instead of row_number).
You can use RANK() analytic function to achieve the goal:
select *
from (select group_num,
points,
rank() over(partition by group_num order by points desc) rank
from results
inner join group_contestant
using (contestant_group_id))
where rank <= 3
order by group_num, points desc;
Here is SQLFiddle to play with.
I found problem in writing subquery with limit 1 to get the top record.
Here is my problem example.
Table Master(id,set)
Table Detail(id,set,code)
i am trying to get the latest code for each set in Master table.
Following is the query which i tried but got an error that limit 1 is not supported for correlated subqueries and it should contain GROUP By clause.
select id,set,(select code from detail where set=master.set order by id desc limit 1) from master;
And the result wolud be like
please help me if this is wrong way, i am new to this vertica database.
thnk you.
I'm not sure about that particular error, but you can use the rank() analytic function to produce results like this:
select id, set, code from (
select M.id, D.set, D.code, rank() over (partition by D.set order by D.id desc) as rank
from detail as D
right outer join master as M
on D.set = M.set) as ranks
where rank = 1
order by id;
The inner subquery uses the rank() function to assign a rank to each row within a set. The outer query just picks out rows with rank 1.
I'm trying to display only the largest group in this group by statement;
SELECT COUNT(type) AS booking, type FROM booking b, room r WHERE r.rno = b.rno AND r.hno = b.hno GROUP BY type;
I modified it so we get this query response now you can see group double is larger then family.
BOOKING TYPE
5 double
2 family
I know there is a HAVING keyword you can add in order display only a count compared to a number so I could do COUNT(type) HAVING > 2 or similar but that's not very dynamic and that would only work in this instance because I know the two amounts.
ORDER BY COUNT(type) DESC LIMIT 1
There isn't a having statement that does this. But you can use rownum with a subquery:
select t.*
from (SELECT COUNT(type) AS booking, type
FROM booking b join
room r
on r.rno = b.rno AND r.hno = b.hno
GROUP BY type
order by count(type) desc
) t
where rownum = 1;
Just order your query..
order by booking desc
regards
TRY this
SELECT COUNT(type) AS booking, type FROM booking b, room r WHERE r.rno = b.rno AND r.hno = b.hno ORDER BY type DESC LIMIT 1
I have a question about Linq select statement. I am new to Linq so any help will be very helpful. I did a lot of research but I still didn't manage to write down correct Linq statement.
I have this two tables and attributes:
Table Titles(title_id(PK), title) and
Table Sales(title_id(PK), qty)
where are title_id and title string values and qty is a number which represents some quantity.
I need to write a select which will take five most selling titles from this two tables.
So, I need to make sum from qty (we can have more records with the same Sales.title_id attribute) and make group by title_id and order by sum(qty) descending and then return attributes title and title_id.
How can I make suitable solution for my question?
Regards,
Dahakka
You can do group join of tables by title_id (each group g will represent all sales of joined title). Then select title description and total of sales for that title. Order result by totals, select title and take required number of top sales titles:
var query = (from t in db.Titles
join s in db.Sales on t.title_id equals s.title_id into g
select new { Title = t.title, Total = g.Sum(x => x.qty) } into ts
orderby ts.Total descending
select ts.Title).Take(5);
Resulting SQL will look like:
SELECT TOP (5) [t2].[title] AS [Title], [t2].[value] AS [Total]
FROM (
SELECT [t0].[title_id], (
SELECT SUM([t1].[qty])
FROM [Sales] AS [t1]
WHERE [t0].[title_id] = [t1].[title_id]
) AS [value]
FROM [Titles] AS [t0]
) AS [t2]
ORDER BY [t2].[value] DESC
Following is the linq query in method syntax
sales.GroupBy(s=>s.title_id)
.Select ( x =>
new {
Title_id = x.Key,
Sales= x.Sum (x=> x.qty)
})
.OrderByDescending(x=>x.Sales).Take(5)
.Join( titles,
sale=>sale.Title_id,
title=> title.title_id,
(sale, title)=> new
{
Title = title.Title,
TotalSales=sale.Sales
}
);