CODEWITHSUNDEEP
c#entity-frameworklinq
Liron Harel
Liron Harel

Reputation: 11247

Get Ids that match specific column values for the same column Id

I have the following table:

I wanted to filter that list, to receive all the c_id's that have all the IDs in a list for the ch_id.

A c_id can have several ch_id's. If for example, the list contains '2,5' integers. I should get the c_id's which each one has at least the values found in that list.

For example, I get in returns c_id 3, because the following rows correspond to the query:

c_id also has ch_id = 6, but it doesn't matter, because it at least need to have those ch_id's that are in the list. I have no idea how to approach this, any help will be appreciated.

I though about grouping the table by c_id, but the table might be very big and I think it might make the query very slow after some time.

I'm trying to achieve this query in LINQ/Entity Framework.

Upvotes: 0

Views: 99

Answers (1)

NetMage
NetMage

Reputation: 26917

Worrying about grouping being too slow sounds like premature optimization to me. Grouping is the right solution, and possibly faster methods would depend on knowing a lot more details about your data.

var ans = from r in src group r by r.c_id into rg where desiredch.All(ach => rg.Any(r => r.ch_id == ach)) select rg.Key;

Upvotes: 1

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