LINQ connection right and left
My task is to refactor some t-sql queries in LINQ. Simple join and left outer join are self explanatory. Here is my code:
string[] leftouter = new string[] { "a", "b", "c", "d", "e" };
string[] inner = new string[] { "a", "b" };
var q = from s1 in leftouter
join s2 in inner on s1 equals s2 into j
from sj in j.DefaultIfEmpty()
select string.Format("Outer: {0} Left: {1}", s1, sj)
Output:
Outer: a Left: a
Outer: b Left: b
Outer: c Left:
Outer: d Left:
Outer: e Left:
This is a simple left join. Now I would like to add a new dataset:
string[] rightouter = new string[] { "c", "d", "e" };
Desired result:
Outer: a Left: a Right:
Outer: b Left: b Right:
Outer: c Left: Right: c
Outer: d Left: Right: d
Outer: e Left: Right: e
How can I reformat LINQ to address this issue? Thanks to
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1 answer
Try the following:
string[] all = {"a", "b", "c", "d", "e"};
string[] left = {"a", "b"};
string[] right = {"c", "d", "e"};
var q = from innerItem in all
join leftItem in left on innerItem equals leftItem into leftItems
join rightItem in right on innerItem equals rightItem into rightItems
from a in leftItems.DefaultIfEmpty()
from b in rightItems.DefaultIfEmpty()
select string.Format("Outer: {0} Left: {1} Right: {2}", innerItem, a, b);
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