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Write query in Entity Framework

I have a query which I ran successfully in SQL Server Management Studio, which returns the table values shown in the screenshot
The query I used is:
SELECT tcoid, COUNT(*) ownleasetank
FROM TankProfile
WHERE ownleasetank = 3
GROUP BY tcoid
Now I'm using Entity Framework to make things easier in my sample project.
I used this method to return the table values as array object:
public async Task<Object> GetLeaseInformationPrincipal()
{
ISOTMSEntities context = new ISOTMSEntities();
var testleaseinfo = from d in context.TankProfiles
join f in context.TankOperators
on d.tcoid equals f.tcoId
where (d.ownleasetank == 3)
select new { f.tcoName, d.ownleasetank } into x
group x by new { x.tcoName } into g
select new
{
tconame = g.Key.tcoName,
ownleasetank = g.Select(x => x.ownleasetank).Count()
};
return testleaseinfo.ToList();
}
but it is not working properly. I also tried other ways, when I use where and groupby method in Entity Framework it doesn't working properly for me.
Does anybody know the solution for this?

It's very simple with LINQ methods:
context.TankProfiles
.Where(t => t.ownleasetank = 3)
.GroupBy(t => t.tcoid)
.Select(g => new {g.Key, g.Count()})
.ToArray();
I have no idea why in your C# version of the query you have such opeartions such join, while your SQL query is very simple. You have to rethink that :)

var c = from t in context.TankProfile
where t.ownleasetank == 3
group t by t.tcoid into g
select new { tcoid=g.Key, ownleasetank=g.Select(x => x.ownleasetank).Count() };
return c.ToList();

SQL to LINQ expres

I'm trying to convert a SQL expression to Linq but I can't make it work, does anyone help?
SELECT
COUNT(descricaoFamiliaNovo) as quantidades
FROM VeiculoComSeminovo
group by descricaoFamiliaNovo
I try this:
ViewBag.familiasCount = db.VeiculoComSeminovo.GroupBy(a => a.descricaoFamiliaNovo).Count();
I need to know how many times each value repeats, but this way it shows me how many distinct values ​​there are in the column.

You can try:
var list = from a in db.VeiculoComSeminovo
group a by a.descricaoFamiliaNovo into g
select new ViewBag{
familiasCount=g.Count()
};
or
var list = db.VeiculoComSeminovo.GroupBy(a => a.descricaoFamiliaNovo)
.Select (g => new ViewBag
{
familiasCount=g.Count()
});
If you need column value:
new ViewBag{
FieldName=g.Key,
familiasCount=g.Count()
};

You don't need the GROUP BY unless there are fields other than the one in COUNT. Try
SELECT
COUNT(descricaoFamiliaNovo) as quantidades
FROM VeiculoComSeminovo
UPDATE, from your comment:
SELECT
COUNT(descricaoFamiliaNovo) as quantidades,
descricaoFamiliaNovo
FROM VeiculoComSeminovo
GROUP BY descricaoFamiliaNovo
That's it as SQL. In LINQ it is something like:
var reponse = db.VeiculoComSeminovo.GroupBy(a => a.descricaoFamiliaNovo)
.Select ( n => new
{Name = n.key,
Count = n.Count()
}
)
Not tested.

Ty all for the help.
I solved the problem using this lines:
// get the objects on db
var list = db.VeiculoComSeminovo.ToList();
// lists to recive data
List<int> totaisFamilia = new List<int>();
List<int> totaisFamiliaComSN = new List<int>();
// loop to cycle through objects and add the values ​​I need to their lists
foreach (var item in ViewBag.familias)
{
totaisFamilia.Add(list.Count(a => a.descricaoFamiliaNovo == item && a.valorSeminovo == null));
totaisFamiliaComSN.Add(list.Count(a => a.descricaoFamiliaNovo == item && a.valorSeminovo != null));
}
The query was a little slow than I expected, but I got the data

How to improve Query with linq

I'm a little bit stuck, I took an new project but there is so timeout issue due to queries.
I don't know the syntax in linq to improve one querie even if i tried multiple times.
The query is :
var contactslist = (User as CustomPrincipal).contacts;
var contacts = from m in db.ADDR_DEST.toList()
from n in contactslist
where m.ADDR_COUNTRY == n.country && m.ADDR_TPL_TYPE == n.tpl_type
select m;
But I want to dosen't launch this query before that i had different parametre so i remove the .toList() for adding some condition with
contacts.where(..);
And then I would like launch my query but i got an error with the type which must be an list<> but in this case it's a Iqueryable.
Can you help me please?
Is there an other way to launch this query after I do all my settings?

You can do something like that:
db.ADDR_DEST.Join(contactslist,
addr => new { country = addr.ADDR_COUNTRY, type = addr.ADDR_TPL_TYPE },
cont => new { country = cont.country, type = cont.tpl_type },
(addr, cont) => addr)
.ToList();
Then, if you want to choose the contactlist that meet certain requirements:
db.ADDR_DEST.Join(contactslist.Where(...).ToList(),
addr => new { country = addr.ADDR_COUNTRY, type = addr.ADDR_TPL_TYPE },
cont => new { country = cont.country, type = cont.tpl_type },
(addr, cont) => addr)
.ToList();
I hope you find it useful

Try (not tested):
var contacts = db.ADDR_DEST.Where(m => m.COUNTRY == contactslist.country
&& m.ADDR_TPL_TYPE == contactslist.tpl_type)
.ToList();
If contactslist is a list then try the following
var contacts = (from addr in db.ADDR_DEST
join cl in contactslist on
new {addr.COUNTRY, addr.ADDR_TPL_TYPE} equals new {cl.country, cl.tpl_type}
select new {addr})
.ToList();
The Linq join is easier to understand than its lambda equivalent!
There are some good examples here

Linq except two IEnumerable queries

I have a two linq query that returns type of IEnumerable. First query returns filtered values and second query return all values I want to except from second query to first query like minus operator in SQL and bind to my listboxs.
my code sample =>
using (ISession session = SessionManager.CurrentSession)
{
IEnumerable<RoleDefinition> roleAssigned = from groupRole in session.Query<GroupRole>()
join roleDef in session.Query<RoleDefinition>() on groupRole.RoleDefinitionId equals
roleDef.RoleDefinitionId
where groupRole.GroupId == SelectedGroupId
orderby roleDef.RoleName
select new RoleDefinition
{
RoleName = roleDef.RoleName
};
IEnumerable<RoleDefinition> roleUnassigned = from grole in session.Query<RoleDefinition>()
orderby grole.RoleName
select new RoleDefinition
{
RoleName = grole.RoleName
};
List<RoleDefinition> lRoleAss = roleAssigned.ToList();
List<RoleDefinition> lRoleUnAss = roleUnassigned.ToList();
lRoleUnAss = lRoleUnAss.Where(x => !lRoleAss.Contains(x)).ToList();
lsbAssigned.DataSource = lRoleAss;
lsbAssigned.TextField = "RoleName";
lsbAssigned.ValueField = "RoleName";
lsbAssigned.DataBind();
lsbUnAssigned.DataSource = lRoleUnAss;
lsbUnAssigned.TextField = "RoleName";
lsbUnAssigned.ValueField = "RoleName";
lsbUnAssigned.DataBind();
}
EDIT => I fixed my code as below and my function works successfully
List<RoleDefiniton> filteredUnassign = lRoleUnAss.Where(def => !lRoleAss.Select(x => x.RoleName).Contains(def.RoleName)).ToList();

Change the following line:
lRoleUnAss = lRoleUnAss.Where(x => !lRoleAss.Contains(x)).ToList();
To
var results = lRoleUnAss.Except(lRoleAss).ToList();
and use results to get the final list.
I declared a new variable because i do not know if you want to keep the initial list intact or not. If you do not mind changing it you may try:
lRoleUnAss = lRoleUnAss.Except(lRoleAss).ToList();

LINQ syntax help: projection and grouping

New to LINQ.. I am curious as to the syntax to do the following SQL query in LINQ
SELECT MAX(TMPS), DAY FROM WEATHERREADINGS
GROUP BY WEATHERREADINGS.DAY
What I have so far:
var minTemps = from ps in ww.WEATHERREADINGS
group ps by ps.DATE.Hour into psByHour
select new
{
HourOfDay = psByHour.Max().DATE.Hour,
MaxTemp = psByHour.Max().TMPS
};
I am getting the following error while doing this:
Exception Details: System.InvalidOperationException: Could not format node 'New' for execution as SQL.
any help greatly appreciated!!

I think the following is what you want. Note that you can get the key from the grouping so there is no need to aggregate there. You need to provide a mechanism to select the item to do the aggregation on for the other.
var maxTemps = from ps in ww.WEATHERREADINGS
group ps by ps.Date.Hour into psByHour
select new
{
HourOfDay = psByHour.Key,
MaxTemp = psByHour.Max( p => p.TMPS )
};

Or the functional approach that i tend to like better:
var result = ww.WEATHERREADINGS
.GroupBy(a => a.Date.Hour)
.Select(a => new
{
Hour = a.Key,
Max = a.Max(b => b.TMPS)
});