How can i find data by field in entity framework?

Question

var searchIds = new List<int>{1,2,3,4,5};
var result = persons.Where(p => p.Locations.Any(l => searchIds.Any(id => l.Id == id)));

sorry for my question, what do you mean by "find data by field?" your code above filters persons based on location with the given ids... so what is the question. — Bagus Tesa, Oct 07 '19 at 09:50
Have a look at: https://stackoverflow.com/questions/41266234/entity-framework-core-in-clause-equivalent — Rand Random, Oct 07 '19 at 09:51
@BagusTesa - his problem is probably that this query doesn't translate to SQL and throws an exception with the latest ef core but he is playing the `guess my error` game so he doesn't want to tell you — Rand Random, Oct 07 '19 at 09:53
It's not clear what you want to achive. Please provide more details. — Andreas Schmidt, Oct 07 '19 at 09:57
@RandRandom, thats a bit weird, i never thought ef core would fail for simple `any` query as long as its iqueryable. given the link you have provided deals with a separate query that retrieves the actual ids. op didnt provide clear question and trying to clarify things are deemed as rude, perhaps i can play the `guess my error` too at later date. thank you for the help sir. — Bagus Tesa, Oct 07 '19 at 09:58
@RandRandom Are you sure this doesn't translate into SQL? It looks OK to me. — DavidG, Oct 07 '19 at 09:59
@DavidG - nope, not sure at all as my `guess my error` game remark tries to imply, I am basically guessing what the error could be - but I thought that EFCore cant do it since it would need to translate the passed list into `select IN` maybe it can do it - all I know is that if it would fail to generate SQL the newest EFCore throws and exception to warn about client evaluation - https://learn.microsoft.com/en-us/ef/core/what-is-new/ef-core-3.0/breaking-changes#linq-queries-are-no-longer-evaluated-on-the-client — Rand Random, Oct 07 '19 at 10:04

score 2 · Accepted Answer · edited Oct 07 '19 at 10:07

Try following :

class Program
{
    static void Main(string[] args)
    {
        List<Person> persons = new List<Person>();
        List<int> searchIds = new List<int> { 1, 2, 3, 4, 5 };
        List<Person> result = persons.Where(p => p.Locations.Any(l => searchIds.Contains(l.Id))).ToList();
    }
}
public class Person
{
    public List<Location> Locations { get; set; }
}
public class Location
{
    public int Id { get; set; }
}

How can i find data by field in entity framework?

1 Answers1