Select record where value equals value of id - linq

Question

This is a simple but hard to describe question
await dbContext.MyTable.AnyAsync(x => x.valueOne == valueOne && x.valueTwo == /*here's my problem*/ );
valueOne is getting passed in as a parameter. The end of the statement in pseudocode would be:
x.valueTwo == the valueTwo of valueOne's record
I know I could pull in valueOne's record and compare from there, but that's clumsier and I feel like there's definitely a better way if only I could find it.
How can I do this in one line?
Edit: clarification
To clarify, the clumsy way would be
var valueOneRecord = await dbContext.MyTable.FirstAsync(x => x.valueOne == valueOne);
exists = await dbContext.MyTable.AnyAsync(x => x.valueOne == valueOne && x.valueTwo == valueOneRecord.valueTwo);
I'm trying to merge this into one line instead of having two database requests

Answer 1

Please try the below
dbContext.MyTable.Join(dbContext.MyTable,
x => new {
x.valueOne,
valueTwo = x.valueOne
},
y => new {
y.valueOne,
y.valueTwo
},
(x, y) => new
{
record1_valueOne = x.valueOne,
record1_valueTwo = x.valueTwo,
record2_valueOne = y.valueOne,
record2_valueTwo = y.valueTwo,
}).Where(x => x.record1_valueOne == valueOneParam && x.record2_valueOne == valueOneParam);

Answer 2

Quite often it is easier for us if you give us your requirement instead of giving us some code and say that the code is not working.
Let's assume that your clumsy method is what you want.
So MyTable is a sequence of objects, let's call them Values. Every Value has at least two properties: ValueOne and ValueTwo. You also have an input value: valueOne.
Suppose you had Schools and Students, every School had a primary key in Id, and a State
class School
{
public int Id {get; set;}
public int CityId {get; set;}
...
}
public class Student
{
public int Id {get; set;}
public string Name {get; set;}
public int CityId {get; set;}
}
A note so strange query would be:
Give me all Students that live in the same City as School 10
int schoolId = 10;
var studentsInSameCityAsSchool10 = dbContext.Schools
// keep only school with Id == 10
.Where(school => school.Id == 10)
// get all Students on these Schools
.GroupJoin(dbContext.Students,
school => school.CityId,
student => student.CityId,
(school, studentsWithSameCityId) => new
{
SchoolId = school.Id,
Students = studentsWithSameCityId.Select(student => new
{
StudentId = student.Id,
Name = student.Name,
...
})
.ToList(),
});
Very straightforward, isn't it. Now let's do a query in just one table:
Give me all Schools with the same CityId as School [10]
int schoolId = 10;
var studentsInSameCityAsSchool10 = dbContext.Schools
// keep only school with Id == 10
.Where(school => school.Id == 10)
// get all Students on these Schools
.GroupJoin(dbContext.Students,
school => school.CityId,
student => student.CityId,
(school, studentsWithSameCityId) => new
{
SchoolId = school.Id,
Students = studentsWithSameCityId.Select(student => new
{
StudentId = student.Id,
Name = student.Name,
...
})
.ToList(),
});
Very straightforward, isn't it. Now let's do a query in just one table:
Give me all Schools with the same CityId as School [10]
int schoolId = 10;
var studentsInSameCityAsSchool10 = dbContext.Schools
// keep only school with Id == 10
.Where(school => school.Id == 10)
// get all Students on these Schools
.Join(dbContext.Students, // Join Schools and Students
school => school.CityId, // from every School take the CityId
student => student.CityId, // from every Student take the CityId
(school, studentWithSameCityId) => new // from every School and every Student
{ // that has the same CityId, make one new
SchoolId = school.Id,
CityId = school.CityId,
StudentThatLiveInCityId = studentWithSameCityId,
});
Very straightforward, isn't it? Now let's do a query in just one table:
Give me all Schools with the same CityId as School [10]
int schoolId = 10;
var studentsInSameCityAsSchool10 = dbContext.Schools
.Where(school => school.Id == 10)
// get all Schools in the same City as School[10]
.Join(dbContext.Schools, // Join Schools and Schools
school1 => school1.CityId, // from every School1 take the CityId
school2 => school2.CityId, // from every School2 take the CityId
(school1, school2WithSameCityId) => new // from every School and every School
{ // that has the same CityId, make one new
...
});
But what does this have to do with my question
Now let's change some of the property names:
class School
{
public int ValueOne {get; set;} // was Id
public int ValueTwo {get; set;} // was CityId
}
int valueOne = 10; // was schoolId
Give me all Schools that have the same ValueTwo (was: located in the same City, or has same cityId) as School with ValueOne == valueOne (was: as School [10])
After the exercizes with Schools and Students this one should be easy:
int valueOne = 10;
var valuesWithSameValueTwo = dbContext.Schools
.Where(value => value.ValueOne == 10)
// get all Values with same ValueTwo Value[10]
.Join(dbContext.Schools, // Join Schools and Schools
val1 => val1.ValueTwo, // from every val1 take the ValueTwo
val2 => val2.ValueTwo, // from every val2 take the ValueTwo
(val, valWithSameValueTwoId) => new
{
...
});
Well, your query is easier: you only want to know if there is any such element. So you don't need to select any properties, and you can stop as soon as you've found one:
// Where and Join:
...
(val, valWithSameValueTwoId) => valWithSameTwoId)
.Any();