I am trying to generate a query that gets the number of entries with dates that occur within each given month. The SQL form of the query I wish to generate goes like this:
SELECT
DatePart(Year, [t1].[StartTime]) as Year,
DatePart(Month, [t1].[StartTime]) as Month,
Count(*) as 'Visits',
Sum([t1].[PageCount]) as 'Total Pageviews'
FROM
[MyDatabase] [t1]
GROUP BY
DatePart(Year, [t1].[StartTime]),
DatePart(Month, [t1].[StartTime])
I tried the following Linq2DB code:
var query = from table in dataContext.MyDataContext(tablePath)
group table by new { table.StartTime.Year, table.StartTime.Month} into grp
select new { Month = grp.Key.Month, Year = grp.Key.Year,
TotalVisitors = grp.Count(),
TotalPageviews = grp.Sum(table2 => table2.PageCount) };
but the SQL query being generated by this is
-- SqlServer.2008 --
SELECT
[t1].[StartTime],
Count(*) as [c1],
Sum([t1].[PageCount]) as [c2]
FROM
[MyDatabase] [t1]
GROUP BY
DatePart(Year, [t1].[StartTime]),
DatePart(Month, [t1].[StartTime]),
[t1].[StartTime]
Why is [t1].[StartTime] rather than the month or year? And why is it grouping by that extra [t1].[StartTime] at the end? How do I generate the SQL query I have above using Linq2DB?
Please use the following workaround with Sql.AsSql function. We are trying to fix this longstanding issue.
var query = from table in dataContext.MyDataContext(tablePath)
group table by new { Sql.AsSql(table.StartTime.Year), Sql.AsSql(table.StartTime.Month)} into grp
select new { Month = Sql.AsSql(grp.Key.Month), Year = Sql.AsSql(grp.Key.Year),
TotalVisitors = grp.Count(),
TotalPageviews = grp.Sum(table2 => table2.PageCount) };
Related
I have following sql statement:
Select
tsl.Transaction_Id,
tsl.State_Id,
MAX(tsl."Timestamp")
from TransactionStatesLog tsl
group by tsl.Transaction_Id
How this statement can be translated to LINQ? I just want to select the whole row, where Timestamp is maximum of the group.
With this code i am able just to select TransactionId and max Timestamp from the group.
var states = (from logs in _context.TransactionStatesLog
group logs by new { logs.TransactionId } into g
select new
{
TransactionId = g.Key,
Timestamp = g.Max(x => x.Timestamp)
}).ToList();
I am working with ef core 3.1
Assuming you forgot to add tsl.State_Id to your SQL as grouping key as follows(otherwise that SQL does not work either):
Select
tsl.Transaction_Id,
tsl.State_Id,
MAX(tsl."Timestamp")
from TransactionStatesLog tsl
group by tsl.Transaction_Id, tsl.State_Id
If I understood you correctly you need to add StateId to grouping statement as well so that you will be able to select StateId and TransactionId.
So this should work:
var states = (from logs in _context.TransactionStatesLog
group logs by new { logs.TransactionId, logs.StateId } into g
select new
{
TransactionId = g.Key.TransactionId,
StateId = g.Key.StateId,
Timestamp = g.Max(x => x.Timestamp)
}).ToList();
See: Group by with multiple columns using lambda
I am failing to convert next SQL code into laravel eloquent:
SELECT t1.template, t1.created_at
FROM sent_emails t1
where created_at = (
select max(created_at) from sent_emails t2 where t2.template = t1.template
)
group by t1.created_at, t1.template
or:
SELECT t1.template, t1.created_at
FROM sent_emails t1
JOIN
(
SELECT Max(created_at) date, template
FROM sent_emails
GROUP BY template
) AS t2
ON t1.template = t2.template
AND t1.created_at = t2.date
group by t1.created_at, t1.template
Both queries return same data set. Creating subquery in separate variable is not an option as I need multiple values to be returned from it.
I also don't know how can I set alias name if I create table using models (and not using DB::), so this is my unsuccessful try:
$sent_emails = SentEmail::where('created_at', function($query) {
SentEmail::where('template', 't1.template')->orderBy('created_at', 'desc');
})->groupBy('template', 'created_at')->get(['template', 'created_at']);
You query should be something like this (I'm not at a computer to test this, so it may require further editing)
$sent_emails = SentEmail::where('created_at', function($query) {
$query->where('created_at', SentEmail::->whereColumn('column_name', 'table.column_name')->orderBy('created_at', 'desc')->max('created_at'));
})->groupBy('template', 'created_at')->get(['template', 'created_at']);
Why can't I use a subquery factoring clause result in the where clause of as depicted in the following sql:
with rpt as(
select * from reports where caseid =
:case_id and rownum=1 order by created desc
)
select
distinct rt.trialid
from
report_trials rt
join
trial_genes tg on rt.id=tg.trialid
where
rt.reportid = rpt.id
and
tg.gene not in('TMB','MS')
The subquery is named rptand used in the select statement's where clause. When executed encountering the following error: ORA-00904: "RPT"."ID": invalid identifier
UPDATE:
In fact nested query for the same thing is also giving me the same issue. The nested subquery is only returning a single column value from a single row:
select
distinct rt.trialid
from
report_trials rt
join
trial_genes tg on rt.id=tg.trialid
where
rt.reportid = (select id from reports where caseid = :case_id and
rownum=1 order by created desc)
and
tg.gene not in('TMB','MS')
You missed to add the table rpt in your query, thus that error.
with rpt as(
select * from reports where caseid =
:case_id and rownum=1 order by created desc
)
select
distinct rt.trialid
from
report_trials rt
join
trial_genes tg on rt.id=tg.trialid
join
rpt on rt.reportid = rpt.id
where
tg.gene not in('TMB','MS')
How could I get this SQL query right in LINQ?
SQL query:
select c.Name, sum(t.value)
from Categories c
join Items i on c.Id = i.CategoryId
join Transactions t on t.ItemId = i.Id
where datepart(YEAR, t.CreatedTime) = 2016
and datepart(MONTH, t.CreatedTime) = 2
group by c.Name
I've tried to do the same in LINQ and got this:
var query = from cat in _context.Categories
join item in _context.Items on cat.Id equals item.CategoryId
join trans in _context.Transactions on item.Id equals trans.ItemId
where trans.CreatedTime.Month == e.RowIndex && trans.CreatedTime.Year == 2016
group new { cat.Name, trans.Value } by cat.Name into g
select new
{
Value = g.Sum(entry => entry.Value)
};
But it seems to be totally wrong, besides not giving me back the category names, it returns wrong values for the sums as well.
I have three tables:
Categories with columns Id and Name
Items with columns Id, Name, CategoryId, LastValue, IsIncome,
Transactions with columns Id, ItemId, Value, CreatedTime, IsIncome
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
}
);