I've come up with the following LINQ, but I can't help thinking that I should be able to do this in one query instead of two. Can anyone help?
The idea is to inner join three tables and group by one.
var q1 = from er in ExportRules
join per in PlaceExportRules on er.ExportRulesID equals per.ExportRulesID
select new
{
PlaceID = per.PlaceID,
Description = er.Description,
Tag = er.TagName,
ExportName = per.ExportName,
ExportAddress = per.ExportAddress
};
var q2 = from p in Places
join rules in q1 on p.PlaceID equals rules.PlaceID into joined2
where joined2.Any()
orderby p.PlaceName
select new {Place = new {p.PlaceID, p.PlaceName}, joined2};
Well, you can just bracket things:
var query = from p in Places
join rules from
(from er in ExportRules
join per in PlaceExportRules
on er.ExportRulesID equals per.ExportRulesID
...)
on p.PlaceId equals rules.PlaceId into joined2
where joined2.Any()
orderby p.PlaceName
select new {Place = new {p.PlaceID, p.PlaceName}, joined2};
However, I'd personally probably leave it as two queries. It's clearer, and won't affect the performance - it's not like the first statement in your code would actually execute the query.