Question

I have 3 tables in my sql database like these :

Documents : (DocID, FileName) //list of all docs that were attached to items
Items : (ItemID, ...) //list of all items
DocumentRelation : (DocID, ItemID) //the relation between docs and items

In my winform application I have showed all records of Items table in a grid view and let user to select several rows of it and then if he press EditAll button another grid view should fill by file name of documents that are related to these selected items but not all of them,

Just each of documents which have relation with ALL selected items

Is there any query (sql or linq) to select these documents?

Answer 1

Try something like:

string query;
foreach (Item in SelectedItems)
{
   query += "select DocID from DocumentRelation where ItemID =" + Item.Id;
   query += "INTERSECT";
}
query -= "INTERSECT";

And exec the Query;