Linq Conditional .Any() Select

Question

How can I perform a conditional select on a column value, where I have a preference over which value is returned. If I can't find the top choice, I settle on the next, if available, and then if not the next, etc. As it looks right now, it would take 3 total queries. Is there a way to simplify this further?

var myResult = string.Empty;

if (myTable.Where(x => x.ColumnValue == "Three").Any())
{
    myResult = "Three"; // Can also be some list.First().Select(x => x.ColumnValue) if that makes it easier;
}
else if (myTable.Where(x => x.ColumnValue == "One").Any())
{
    myResult = "One";
}
else if (myTable.Where(x => x.ColumnValue == "Two").Any())
{
    myResult = "Two";
}
else
{
    myResult = "Four";
}

Answer 1

You could use a string[] for your preferences:

string[] prefs = new[]{ "One", "Two", "Three" };
string myResult = prefs.FirstOrDefault(p => myTable.Any(x => x.ColumnValue == p));
if(myResult == null) myResult = "Four";

Edit Enumerable.Join is a very efficient hash table method, it also needs only one query:

string myResult = prefs.Select((pref, index) => new { pref, index })
    .Join(myTable, xPref => xPref.pref, x => x.ColumnValue, (xPref, x) => new { xPref, x })
    .OrderBy(x => x.xPref.index)
    .Select(x => x.x.ColumnValue)
    .DefaultIfEmpty("Four")
    .First();

Demo