{"id":304643,"date":"2020-06-01T15:00:29","date_gmt":"2020-06-01T15:00:29","guid":{"rendered":"http:\/\/savepearlharbor.com\/?p=304643"},"modified":"-0001-11-30T00:00:00","modified_gmt":"-0001-11-29T21:00:00","slug":"","status":"publish","type":"post","link":"https:\/\/savepearlharbor.com\/?p=304643","title":{"rendered":"Outer Join \u0432 LINQ"},"content":{"rendered":"\n<div class=\"post__text post__text-html post__text_v1\" id=\"post-content-body\" data-io-article-url=\"https:\/\/habr.com\/ru\/post\/504854\/\">LINQ \u2014 \u043a\u0430\u043a \u043c\u043d\u043e\u0433\u043e \u0431\u044b\u043b\u043e \u043f\u0440\u0438\u0434\u0443\u043c\u0430\u043d\u043e \u0432 C# \u043b\u0438\u0448\u044c \u0434\u043b\u044f \u0442\u043e\u0433\u043e \u0447\u0442\u043e\u0431\u044b \u043c\u044b \u043c\u043e\u0433\u043b\u0438 \u043d\u0430\u0441\u043b\u0430\u0436\u0434\u0430\u0442\u044c\u0441\u044f \u043f\u0440\u0435\u043b\u0435\u0441\u0442\u044f\u043c\u0438 Language Integrated Query. \u0410 \u0438\u043c\u0435\u043d\u043d\u043e:   <\/p>\n<ul>\n<li>Generics<\/li>\n<li>Extension Methods<\/li>\n<li>Lamda expressions<\/li>\n<li>Expression trees<\/li>\n<li>Anonumus types<\/li>\n<li>Object initializers<\/li>\n<li>Type inferring<\/li>\n<\/ul>\n<p>   \u0418 \u044d\u0442\u043e \u0432\u0441\u0435 \u0447\u0442\u043e\u0431\u044b \u043c\u044b \u043c\u043e\u0433\u043b\u0438 \u043d\u0430\u043f\u0438\u0441\u0430\u0442\u044c \u043d\u0435\u0447\u0442\u043e \u0432\u0440\u043e\u0434\u0435 \u0442\u0430\u043a\u043e\u0433\u043e:   <\/p>\n<pre><code class=\"cs\">\tvar query =  \t\tfrom itemA in listA \t\tjoin itemB in listB \t\t\ton itemA.Key equals itemB.Key \t\tselect new {itemA, itemB}; \t<\/code><\/pre>\n<p>   \u041d\u0435\u043b\u044c\u0437\u044f \u043d\u0435 \u0441\u043e\u0433\u043b\u0430\u0441\u0438\u0442\u044c\u0441\u044f \u2014 \u0432\u043f\u0435\u0447\u0442\u0430\u043b\u044f\u0435\u0442.<\/p>\n<p>  \u0418 \u0441\u0440\u0435\u0434\u0438 \u0432\u0441\u0435\u0433\u043e \u044d\u0442\u043e\u0433\u043e \u0441\u0438\u043d\u0442\u0430\u043a\u0441\u0438\u0447\u0435\u0441\u043a\u043e\u0433\u043e \u0441\u0430\u0445\u0430\u0440\u0430 \u0431\u044b\u043b\u0430 \u043b\u043e\u0436\u043a\u0430 \u0434\u0435\u0433\u0434\u044f \u043a\u043e\u0442\u043e\u0440\u0430\u044f \u043c\u043d\u0435 \u043d\u0435 \u0434\u0430\u0432\u0430\u043b\u0430 \u043d\u043e\u0440\u043c\u0430\u043b\u044c\u043d\u043e \u0432\u044b\u0441\u043f\u0430\u0442\u044c\u0441\u044f \ud83d\ude42<br \/>   \u042d\u0442\u043e \u0442\u043e\u0442\u0430\u043b\u044c\u043d\u043e\u0435 \u043e\u0442\u0441\u0443\u0442\u0441\u0442\u0432\u0438\u0435 \u043f\u043e\u0434\u0434\u0435\u0440\u0436\u043a\u0438 OUTER JOIN. \u041d\u043e \u043a\u0430\u043a \u043e\u043a\u0430\u0437\u0430\u043b\u043e\u0441\u044c \u0434\u0435\u0433\u043e\u0442\u044c \u0441 \u043b\u0435\u0433\u043a\u043e\u0441\u0442\u044c\u044e \u043f\u0440\u0435\u0432\u0440\u0430\u0449\u0430\u0435\u0442\u0441\u044f\u2026 \u043f\u0440\u0435\u0432\u0440\u0430\u0449\u0430\u0435\u0442\u0441\u044f\u2026 \u043f\u0440\u0435\u0432\u0440\u0430\u0449\u0430\u0435\u0442\u0441\u044f\u2026<br \/>   <a name=\"habracut\"><\/a><br \/>  \u2026 \u0432 \u0435\u0449\u0435 \u043e\u0434\u0438\u043d \u00ab\u0441\u0438\u043d\u0442\u0430\u043a\u0441\u0438\u0447\u0435\u0441\u043a\u0438\u0439 \u0441\u0430\u0445\u0430\u0440\u00bb.<\/p>\n<p>  \u0422\u0435\u043c, \u043a\u0442\u043e \u043f\u044b\u0442\u0430\u043b\u0441\u044f \u043d\u0430\u0439\u0442\u0438 \u0440\u0435\u0448\u0435\u043d\u0438\u0435 \u0434\u043b\u044f LEFT OUTER JOIN \u0432 \u0438\u043d\u0442\u0435\u0440\u043d\u0435\u0442\u0435, \u043d\u0430\u0432\u0435\u0440\u043d\u044f\u043a\u0430 \u0437\u043d\u0430\u043a\u043e\u043c\u043e \u043f\u043e\u0434\u043e\u0431\u043d\u043e\u0435 \u0440\u0435\u0448\u0435\u043d\u0438\u0435:   <\/p>\n<pre><code class=\"cs\">\tvar query =  \t\tfrom itemA in listA \t\tjoin itemB in listB \t\t\ton itemA.Key equals itemB.Key into outer \t\tfrom itemO in outer.DefaultIfEmpty() \t\tselect new {itemA, itemO}; \t<\/code><\/pre>\n<p>   \u041f\u043e\u0434\u043e\u0431\u043d\u0430\u044f \u043a\u043e\u043d\u0441\u0442\u0440\u0443\u043a\u0446\u0438\u044f \u044f\u0432\u043d\u043e \u043d\u0430 \u043f\u043e\u0440\u044f\u0434\u043e\u043a \u0437\u0430\u043f\u0443\u0442\u044b\u0432\u0430\u0435\u0442 \u043f\u043e\u043d\u0438\u043c\u0430\u043d\u0438\u0435 \u0438 \u0443\u0441\u043b\u043e\u0436\u043d\u044f\u0435\u0442 \u0438 \u0431\u0435\u0437 \u0442\u043e\u0433\u043e \u043f\u0440\u043e\u0441\u0442\u0443\u044e \u043a\u043e\u043d\u0441\u0442\u0440\u0443\u043a\u0446\u0438\u044e. \u0410 \u044d\u0442\u043e \u043b\u0438\u0448\u044c \u0437\u0430\u043c\u0435\u043d\u0430 INNER JOIN \u043d\u0430 LEFT OUTER JOIN. \u0427\u0442\u043e\u0431\u044b \u043d\u0435 \u043f\u0440\u043e\u0434\u043e\u043b\u0436\u0430\u0442\u044c \u0448\u043e\u043a\u0438\u0440\u043e\u0432\u0430\u0442\u044c, \u043f\u0440\u0438\u043c\u0435\u0440 \u0441 FULL OUTER JOIN \u043f\u0440\u0438\u0432\u043e\u0434\u0438\u0442\u044c \u043d\u0435 \u0431\u0443\u0434\u0443.<\/p>\n<p>  \u041a\u0430\u0437\u0430\u043b\u043e\u0441\u044c \u0431\u044b \u043a\u0430\u043a \u0431\u044b\u043b\u043e \u0431\u044b \u043f\u0440\u043e\u0441\u0442\u043e \u0435\u0441\u043b\u0438 \u0431\u044b \u043c\u043e\u0433\u043b\u0438 \u043d\u0430\u043f\u0438\u0441\u0430\u0442\u044c \u0432\u043e\u0442 \u0442\u0430\u043a:   <\/p>\n<pre><code class=\"cs\">\tvar query =  \t\tfrom itemA in listA \t\tleft join itemB in listB \t\t\ton itemA.Key equals itemB.Key \t\tselect new {itemA, itemB}; \t<\/code><\/pre>\n<p>   \u0438\u043b\u0438 \u0442\u0430\u043a   <\/p>\n<pre><code class=\"cs\">\tvar query =  \t\tfrom itemA in listA \t\tfull join itemB in listB \t\t\ton itemA.Key equals itemB.Key \t\tselect new {itemA, itemB}; \t<\/code><\/pre>\n<p>   \u0410\u043d \u043d\u0435\u0442. \u0410\u0432\u0442\u043e\u0440\u044b C# \u043d\u0430\u043c \u0442\u0430\u043a\u043e\u0433\u043e \u0443\u0434\u043e\u0432\u043e\u043b\u044c\u0441\u0442\u0432\u0438\u044f \u043d\u0435 \u043f\u0440\u0435\u0434\u043e\u0441\u0442\u0430\u0432\u0438\u043b\u0438. \u041d\u0443 \u043d\u0435 \u0431\u0435\u0434\u0430. \u0412\u0441\u0435 \u0436\u0435 \u043e\u043d\u0438 \u043f\u043e\u0437\u0432\u043e\u043b\u044f\u0442 \u043d\u0430\u043c \u044d\u0442\u043e \u0441\u0434\u0435\u043b\u0430\u0442\u044c \u0441\u0430\u043c\u043e\u0441\u0442\u043e\u044f\u0442\u0435\u043b\u044c\u043d\u043e, \u0445\u043e\u0442\u044c \u0438 \u043d\u0435 \u0442\u0430\u043a\u0438\u043c \u043a\u0440\u0430\u0441\u0438\u0432\u044b\u043c \u0441\u043f\u043e\u0441\u043e\u0431\u043e\u043c.<\/p>\n<p>  \u041d\u0430\u0447\u043d\u0435\u043c \u0441 \u0442\u043e\u0433\u043e, \u0447\u0442\u043e \u0435\u0441\u043b\u0438 \u043a\u0442\u043e \u0442\u043e \u0432\u0430\u043c \u0441\u043a\u0430\u0436\u0435\u0442, \u0447\u0442\u043e LINQ \u0438 \u0438\u043d\u0442\u0435\u0440\u0444\u0435\u0439\u0441 System.Collections.Generic.IEnumerable \u0438\u043c\u0435\u044e\u0442 \u0447\u0442\u043e \u0442\u043e \u043e\u0431\u0449\u0435\u0435 \u0438 \u043d\u0435 \u043c\u043e\u0433\u0443\u0442 \u0441\u0443\u0449\u0435\u0441\u0442\u0432\u043e\u0432\u0430\u0442\u044c \u043f\u043e \u043e\u0442\u0434\u0435\u043b\u044c\u043d\u043e\u0441\u0442\u0438 \u043c\u043e\u0436\u0435\u0442\u0435 \u0441\u043c\u0435\u043b\u043e \u0440\u0430\u0441\u0441\u043c\u0435\u044f\u0442\u044c\u0441\u044f \u0432 \u043b\u0438\u0446\u043e\u2026<\/p>\n<p>  \u041a\u043e\u043d\u0441\u0442\u0440\u0443\u043a\u0446\u0438\u044f  <\/p>\n<pre><code class=\"cs\">\tvar query =  \t\tfrom itemA in listA \t\tjoin itemB in listB \t\t\ton itemA.Key equals itemB.Key \t\tselect new {itemA, itemB}; <\/code><\/pre>\n<p>   \u043f\u0440\u043e\u0441\u0442\u043e \u043d\u0430\u043f\u0440\u043e\u0441\u0442\u043e \u0442\u0440\u0430\u043d\u0441\u043b\u0438\u0440\u0443\u0435\u0442\u0441\u044f \u043a\u043e\u043c\u043f\u0438\u043b\u044f\u0442\u043e\u0440\u043e\u043c \u0432 \u0441\u043b\u0435\u0434\u0443\u044e\u0449\u0443\u044e \u043f\u043e\u0441\u043b\u0435\u0434\u043e\u0432\u0430\u0442\u0435\u043b\u044c\u043d\u043e\u0441\u0442\u044c \u0441\u0438\u043c\u0432\u043e\u043b\u043e\u0432:  <\/p>\n<pre><code class=\"cs\">\tvar query = listA.Join(listB, itemA =&gt; itemA.Key, itemB =&gt; itemB.Key, (itemA, itemB) =&gt; new {itemA, itemB});<\/code><\/pre>\n<p>  \u0438 \u0430\u0431\u0441\u043e\u043b\u044e\u0442\u043d\u043e \u043d\u0435 \u0432\u0430\u0436\u043d\u043e \u043a\u0430\u043a\u043e\u0433\u043e \u0442\u0438\u043f\u0430 \u043f\u0435\u0440\u0435\u043c\u0435\u043d\u043d\u044b\u0435 listA \u0438 listB. \u041f\u0440\u0435\u0434\u043f\u043e\u043b\u043e\u0436\u0438\u043c \u0447\u0442\u043e listA \u043f\u0435\u0440\u0435\u043c\u0435\u043d\u043d\u0430\u044f \u0442\u0438\u043f\u0430 TypeA, \u0430 \u043f\u0435\u0440\u043c\u0435\u043c\u0435\u043d\u043d\u0430\u044f itemB \u0442\u0438\u043f\u0430 TypeB. \u0422\u0430\u043a \u0432\u043e\u0442, \u0435\u0441\u043b\u0438 TypeA \u0438 TypeB \u0441\u043e\u0434\u0435\u0440\u0430\u0436\u0430\u0442 \u0441\u0432\u043e\u0439\u0441\u0442\u0432\u043e \u0438\u043b\u0438 \u043f\u043e\u043b\u0435 \u0441 \u0438\u043c\u0435\u043d\u0435\u043c Key, TypeA \u0441\u043e\u0434\u0435\u0440\u0436\u0438\u0442 \u043c\u0435\u0442\u043e\u0434 Join() \u0441 4\u043c\u044f \u0430\u0440\u0433\u0443\u043c\u0435\u043d\u0442\u0430\u043c\u0438. \u042d\u0442\u043e\u0442 LINQ \u0437\u0430\u043f\u0440\u043e\u0441 \u0441\u0432\u043e\u0431\u043e\u0434\u043d\u043e \u043e\u0442\u043a\u043e\u043c\u043f\u0438\u043b\u0438\u0440\u0443\u0435\u0442\u0441\u044f. <\/p>\n<p>  \u041f\u0440\u0438 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u043d\u0438\u0438 \u0432 LINQ \u043f\u0435\u0440\u0435\u043c\u0435\u043d\u043d\u044b\u0445 \u043a\u043e\u0442\u043e\u0440\u044b\u0435 \u0440\u0435\u0430\u043b\u0438\u0437\u0443\u044e\u0442 \u0441\u0442\u0430\u043d\u0434\u0430\u0440\u0442\u043d\u044b\u0439 \u0438\u043d\u0442\u0435\u0440\u0444\u0435\u0439\u0441 IEnumerable \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u0443\u0435\u0442\u0441\u044f \u043c\u0435\u0442\u043e\u0434 \u0440\u0430\u0441\u0448\u0438\u0440\u0435\u043d\u0438\u044f   <\/p>\n<pre><code class=\"cs\">public class System.Linq.Enumerable { \t\tpublic static IEnumerable&lt;TResult&gt; Join&lt;TOuter, TInner, TKey, TResult&gt;(this IEnumerable&lt;TOuter&gt; outer, IEnumerable&lt;TInner&gt; inner, Func&lt;TOuter, TKey&gt; outerKeySelector, Func&lt;TInner, TKey&gt; innerKeySelector, Func&lt;TOuter, TInner, TResult&gt; resultSelector) {...} } <\/code><\/pre>\n<p>  \u0421\u043e\u0431\u0441\u0442\u0432\u0435\u043d\u043d\u043e \u044d\u0442\u043e\u0442 \u043c\u0435\u0442\u043e\u0434 \u0438 \u043f\u0440\u043e\u0438\u0437\u0432\u043e\u0434\u0438\u0442 \u0445\u043e\u0440\u043e\u0448\u043e \u0438\u0437\u0432\u0435\u0441\u0442\u043d\u044b\u0439 \u043d\u0430\u043c INNER JOIN. \u0418 \u0432\u043e\u0442 \u0442\u0435\u043f\u0435\u0440\u044c \u043d\u0430\u0447\u0438\u043d\u0430\u0435\u0442\u0441\u044f \u0443\u043b\u0438\u0447\u043d\u0430\u044f \u043c\u0430\u0433\u0438\u044f. \u0427\u0442\u043e\u0431\u044b \u0440\u0435\u0430\u043b\u0438\u0437\u043e\u0432\u0430\u0442\u044c \u043d\u0430\u043c LEFT \/ RIGHT \/ FULL OUTER JOIN (\u0438\u043b\u0438 JOIN \u043a\u0430\u043a\u043e\u0439 \u0432\u0430\u0448\u0435\u0439 \u0434\u0443\u0448\u0435 \u0431\u0443\u0434\u0435\u0442 \u0443\u0433\u043e\u0434\u0435\u043d) \u043d\u0435\u043e\u0431\u0445\u043e\u0434\u0438\u043c\u043e \u043f\u043e\u0434\u043c\u0435\u043d\u0438\u0442\u044c \u0432\u044b\u0437\u043e\u0432 \u0441\u0442\u0430\u043d\u0434\u0430\u0440\u0442\u043d\u043e\u0433\u043e \u043c\u0435\u0442\u043e\u0434\u0430 \u043d\u0430 \u0440\u0435\u0430\u043b\u0438\u0437\u043e\u0432\u0430\u043d\u044b\u0439 \u043d\u0430\u043c\u0438. \u0427\u0442\u043e\u0431\u044b \u044d\u0442\u043e \u0441\u0434\u0435\u043b\u0430\u0442\u044c<br \/>   \u043d\u0430\u0434\u043e \u043f\u0435\u0440\u0435\u043c\u0435\u043d\u043d\u0443\u044e listA \u043f\u0440\u0435\u043e\u0431\u0440\u0430\u0437\u043e\u0432\u0430\u0442\u044c \u043a\u0430\u043a\u0438\u043c \u0442\u043e \u043e\u0431\u0440\u0430\u0437\u043e\u043c \u0432 \u0442\u0438\u043f \u043a\u043e\u0442\u043e\u0440\u044b\u0439 \u043c\u044b \u043c\u043e\u0436\u0435\u043c \u043a\u043e\u043d\u0442\u0440\u043e\u043b\u0438\u0440\u043e\u0432\u0430\u0442\u044c.<\/p>\n<p>  \u0420\u0435\u0430\u043b\u0438\u0437\u043e\u0432\u0430\u0432 \u0434\u0432\u0430 \u0441\u043b\u0435\u0434\u0443\u044e\u0449\u0438\u0445 \u043a\u043b\u0430\u0441\u0441\u0430:  <\/p>\n<pre><code class=\"cs\">public class JoinedEnumerable&lt;T&gt; : IEnumerable&lt;T&gt; { \tpublic readonly IEnumerable&lt;T&gt; Source; \tpublic bool IsOuter;  \tpublic JoinedEnumerable(IEnumerable&lt;T&gt; source) { Source = source; }  \tIEnumerator&lt;T&gt; IEnumerable&lt;T&gt;.GetEnumerator() { return Source.GetEnumerator(); } \tIEnumerator IEnumerable.GetEnumerator() { return Source.GetEnumerator(); } }  public static class JoinedEnumerable { \tpublic static JoinedEnumerable&lt;TElement&gt; Inner&lt;TElement&gt;(this IEnumerable&lt;TElement&gt; source) \t{ \t\treturn Wrap(source, false); \t}  \tpublic static JoinedEnumerable&lt;TElement&gt; Outer&lt;TElement&gt;(this IEnumerable&lt;TElement&gt; source) \t{ \t\treturn Wrap(source, true); \t}  \tpublic static JoinedEnumerable&lt;TElement&gt; Wrap(IEnumerable&lt;TElement&gt; source, bool isOuter) \t{ \t\tJoinedEnumerable&lt;TElement&gt; joinedSource  \t\t\t= source as JoinedEnumerable&lt;TElement&gt; ??  \t\t\t\tnew JoinedEnumerable&lt;TElement&gt;(source); \t\tjoinedSource.IsOuter = isOuter; \t\treturn joinedSource; \t} } <\/code><\/pre>\n<p>  \u043c\u044b \u0437\u0430\u043f\u0440\u043e\u0441\u0442\u043e \u043f\u0438\u0448\u0435\u043c \u0441\u043b\u0435\u0434\u0443\u044e\u0449\u0438\u0439 LINQ \u0437\u0430\u043f\u0440\u043e\u0441  <\/p>\n<pre><code class=\"cs\">\tvar query =  \t\tfrom itemA in listA.Outer() \t\tjoin itemB in listB \t\t\ton itemA.Key equals itemB.Key \t\tselect new {itemA, itemB}; <\/code><\/pre>\n<p>  \u0438 \u0442\u0435\u043f\u0435\u0440\u044c \u0440\u0435\u0430\u043b\u0438\u0437\u043e\u0432\u0430\u0432 \u043c\u0435\u0442\u043e\u0434 \u0440\u0430\u0441\u0448\u0438\u0440\u0435\u043d\u0438\u044f Join \u0434\u043b\u044f \u043a\u043b\u0430\u0441\u0441\u0430 JoinedEnumerable \u043d\u0443\u0436\u043d\u044b\u043c \u043d\u0430\u043c \u043e\u0431\u0440\u0430\u0437\u043e\u043c \u043f\u043e\u043b\u0443\u0447\u0430\u0435\u043c \u0432\u0441\u0435 \u0447\u0442\u043e \u043d\u0430\u043c \u043d\u0443\u0436\u043d\u043e.<\/p>\n<p>  \u0410 \u0432\u043e\u0442 \u0441\u043e\u0431\u0441\u0442\u0432\u0435\u043d\u043d\u043e \u0438 \u043c\u0435\u0442\u043e\u0434\u044b \u0440\u0430\u0441\u0448\u0438\u0440\u0435\u043d\u0438\u044f:  <\/p>\n<pre><code class=\"cs\">public static IEnumerable&lt;TResult&gt; Join&lt;TOuter, TInner, TKey, TResult&gt;(this JoinedEnumerable&lt;TOuter&gt; outer, IEnumerable&lt;TInner&gt; inner, Func&lt;TOuter, TKey&gt; outerKeySelector, Func&lt;TInner, TKey&gt; innerKeySelector, Func&lt;TOuter, TInner, TResult&gt; resultSelector, IEqualityComparer&lt;TKey&gt; comparer = null) { \tif (outer == null) throw new ArgumentNullException(&quot;outer&quot;); \tif (inner == null) throw new ArgumentNullException(&quot;inner&quot;); \tif (outerKeySelector == null) throw new ArgumentNullException(&quot;outerKeySelector&quot;); \tif (innerKeySelector == null) throw new ArgumentNullException(&quot;innerKeySelector&quot;); \tif (resultSelector == null) throw new ArgumentNullException(&quot;resultSelector&quot;);  \tbool leftOuter = outer.IsOuter; \tbool rightOuter = (inner is JoinedEnumerable&lt;TInner&gt;) &amp;&amp; ((JoinedEnumerable&lt;TInner&gt;)inner).IsOuter;  \tif (leftOuter &amp;&amp; rightOuter) \t\treturn FullOuterJoin(outer, inner, outerKeySelector, innerKeySelector, resultSelector, comparer);  \tif (leftOuter) \t\treturn LeftOuterJoin(outer, inner, outerKeySelector, innerKeySelector, resultSelector, comparer);  \tif (rightOuter) \t\treturn RightOuterJoin(outer, inner, outerKeySelector, innerKeySelector, resultSelector, comparer);  \treturn Enumerable.Join(outer, inner, outerKeySelector, innerKeySelector, resultSelector, comparer); }  public static IEnumerable&lt;TResult&gt; LeftOuterJoin&lt;TOuter, TInner, TKey, TResult&gt;(this IEnumerable&lt;TOuter&gt; outer, IEnumerable&lt;TInner&gt; inner, Func&lt;TOuter, TKey&gt; outerKeySelector, Func&lt;TInner, TKey&gt; innerKeySelector, Func&lt;TOuter, TInner, TResult&gt; resultSelector, IEqualityComparer&lt;TKey&gt; comparer = null) { \tvar innerLookup = inner.ToLookup(innerKeySelector, comparer);  \tforeach (var outerItem in outer) \t\tforeach (var innerItem in innerLookup[outerKeySelector(outerItem)].DefaultIfEmpty()) \t\t\tyield return resultSelector(outerItem, innerItem); }  public static IEnumerable&lt;TResult&gt; RightOuterJoin&lt;TOuter, TInner, TKey, TResult&gt;(this IEnumerable&lt;TOuter&gt; outer, IEnumerable&lt;TInner&gt; inner, Func&lt;TOuter, TKey&gt; outerKeySelector, Func&lt;TInner, TKey&gt; innerKeySelector, Func&lt;TOuter, TInner, TResult&gt; resultSelector, IEqualityComparer&lt;TKey&gt; comparer = null) { \tvar outerLookup = outer.ToLookup(outerKeySelector, comparer);  \tforeach (var innerItem in inner) \t\tforeach (var outerItem in outerLookup[innerKeySelector(innerItem)].DefaultIfEmpty()) \t\t\tyield return resultSelector(outerItem, innerItem); }  public static IEnumerable&lt;TResult&gt; FullOuterJoin&lt;TOuter, TInner, TKey, TResult&gt;(this IEnumerable&lt;TOuter&gt; outer, IEnumerable&lt;TInner&gt; inner, Func&lt;TOuter, TKey&gt; outerKeySelector, Func&lt;TInner, TKey&gt; innerKeySelector, Func&lt;TOuter, TInner, TResult&gt; resultSelector, IEqualityComparer&lt;TKey&gt; comparer = null) { \tvar outerLookup = outer.ToLookup(outerKeySelector, comparer); \tvar innerLookup = inner.ToLookup(innerKeySelector, comparer);  \tforeach (var innerGrouping in innerLookup) \t\tif (!outerLookup.Contains(innerGrouping.Key)) \t\t\tforeach (TInner innerItem in innerGrouping) \t\t\t\tyield return resultSelector(default(TOuter), innerItem);  \tforeach (var outerGrouping in outerLookup) \t\tforeach (var innerItem in innerLookup[outerGrouping.Key].DefaultIfEmpty()) \t\t\tforeach (var outerItem in outerGrouping) \t\t\t\tyield return resultSelector(outerItem, innerItem); } <\/code><\/pre>\n<p>  \u0412\u0443\u0430\u043b\u044f\u2026<\/p>\n<p>  \u041a\u0440\u0430\u0441\u0438\u0432\u044b\u0439 LEFT OUTER JOIN:  <\/p>\n<pre><code class=\"cs\">\tvar query =  \t\tfrom itemA in listA.Outer() \t\tjoin itemB in listB \t\t\ton itemA.Key equals itemB.Key \t\tselect new {itemA, itemB}; <\/code><\/pre>\n<p>  \u041a\u0440\u0430\u0441\u0438\u0432\u044b\u0439 RIGHT OUTER JOIN:  <\/p>\n<pre><code class=\"cs\">\tvar query =  \t\tfrom itemA in listA.Inner() \t\tjoin itemB in listB.Outer() \t\t\ton itemA.Key equals itemB.Key \t\tselect new {itemA, itemB}; <\/code><\/pre>\n<p>  \u041a\u0440\u0430\u0441\u0438\u0432\u044b\u0439 FULL OUTER JOIN:  <\/p>\n<pre><code class=\"cs\">\tvar query =  \t\tfrom itemA in listA.Outer() \t\tjoin itemB in listB.Outer() \t\t\ton itemA.Key equals itemB.Key \t\tselect new {itemA, itemB}; <\/code><\/pre>\n<p>  \u0422\u0435\u043f\u0435\u0440\u044c \u043f\u0440\u0438 \u0436\u0435\u043b\u0430\u043d\u0438\u0438 \u0432\u044b \u043c\u043e\u0436\u0435\u0442\u0435 \u0438\u0441\u043f\u043e\u043b\u044c\u0437\u043e\u0432\u0430\u0442\u044c \u0438 \u0441\u0432\u043e\u0439 \u043f\u043e\u0434\u0445\u043e\u0434 \u2014 \u0442\u0430\u043a \u043a\u0430\u043a \u043f\u043e\u043b\u0435 \u0434\u043b\u044f \u0444\u0430\u043d\u0442\u0430\u0437\u0438\u0438 \u0437\u0434\u0435\u0441\u044c \u0433\u0440\u043e\u043c\u0430\u0434\u043d\u0435\u0439\u0448\u0435\u0435. \u0423 \u043c\u0435\u043d\u044f \u0432 \u0437\u0430\u0433\u0430\u0448\u043d\u0438\u043a\u0435 \u0435\u0441\u0442\u044c \u0435\u0449\u0435 \u043d\u0435\u0441\u043a\u043e\u043b\u044c\u043a\u043e \u0438\u043d\u0435\u0442\u0435\u0440\u0441\u043d\u044b\u0445 \u0440\u0435\u0448\u0435\u043d\u0438\u0439 \u0434\u043b\u044f \u0440\u0435\u0430\u043b\u0438\u0437\u0430\u0446\u0438\u0438 \u0432\u043a\u0443\u0441\u043d\u043e\u0441\u0442\u0435\u0439. \u0411\u0443\u0434\u0435\u0442 \u0432\u0440\u0435\u043c\u044f \u043e\u0431\u044f\u0437\u0430\u0442\u0435\u043b\u044c\u043d\u043e \u043f\u043e\u0434\u0435\u043b\u044e\u0441\u044c \u0438\u043c\u0438. <\/p>\n<p>  \u0421\u043f\u0430\u0441\u0438\u0431\u043e \u0437\u0430 \u0432\u043d\u0438\u043c\u0430\u043d\u0438\u0435. <br \/>  \u0414\u0430 \u043f\u0440\u0435\u0431\u0443\u0434\u0435\u0442 \u0441 \u0432\u0430\u043c\u0438 \u0421\u0418\u041b\u0410!<\/div>\n<p> \u0441\u0441\u044b\u043b\u043a\u0430 \u043d\u0430 \u043e\u0440\u0438\u0433\u0438\u043d\u0430\u043b \u0441\u0442\u0430\u0442\u044c\u0438 <a href=\"https:\/\/habr.com\/ru\/post\/504854\/\"> https:\/\/habr.com\/ru\/post\/504854\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"\n<div class=\"post__text post__text-html post__text_v1\" id=\"post-content-body\" data-io-article-url=\"https:\/\/habr.com\/ru\/post\/504854\/\">LINQ \u2014 \u043a\u0430\u043a \u043c\u043d\u043e\u0433\u043e \u0431\u044b\u043b\u043e \u043f\u0440\u0438\u0434\u0443\u043c\u0430\u043d\u043e \u0432 C# \u043b\u0438\u0448\u044c \u0434\u043b\u044f \u0442\u043e\u0433\u043e \u0447\u0442\u043e\u0431\u044b \u043c\u044b \u043c\u043e\u0433\u043b\u0438 \u043d\u0430\u0441\u043b\u0430\u0436\u0434\u0430\u0442\u044c\u0441\u044f \u043f\u0440\u0435\u043b\u0435\u0441\u0442\u044f\u043c\u0438 Language Integrated Query. \u0410 \u0438\u043c\u0435\u043d\u043d\u043e:   <\/p>\n<ul>\n<li>Generics<\/li>\n<li>Extension Methods<\/li>\n<li>Lamda expressions<\/li>\n<li>Expression trees<\/li>\n<li>Anonumus types<\/li>\n<li>Object initializers<\/li>\n<li>Type inferring<\/li>\n<\/ul>\n<p>   \u0418 \u044d\u0442\u043e \u0432\u0441\u0435 \u0447\u0442\u043e\u0431\u044b \u043c\u044b \u043c\u043e\u0433\u043b\u0438 \u043d\u0430\u043f\u0438\u0441\u0430\u0442\u044c \u043d\u0435\u0447\u0442\u043e \u0432\u0440\u043e\u0434\u0435 \u0442\u0430\u043a\u043e\u0433\u043e:   <\/p>\n<pre><code class=\"cs\">\tvar query =  \t\tfrom itemA in listA \t\tjoin itemB in listB \t\t\ton itemA.Key equals itemB.Key \t\tselect new {itemA, itemB}; \t<\/code><\/pre>\n<p>   \u041d\u0435\u043b\u044c\u0437\u044f \u043d\u0435 \u0441\u043e\u0433\u043b\u0430\u0441\u0438\u0442\u044c\u0441\u044f \u2014 \u0432\u043f\u0435\u0447\u0442\u0430\u043b\u044f\u0435\u0442.<\/p>\n<p>  \u0418 \u0441\u0440\u0435\u0434\u0438 \u0432\u0441\u0435\u0433\u043e \u044d\u0442\u043e\u0433\u043e \u0441\u0438\u043d\u0442\u0430\u043a\u0441\u0438\u0447\u0435\u0441\u043a\u043e\u0433\u043e \u0441\u0430\u0445\u0430\u0440\u0430 \u0431\u044b\u043b\u0430 \u043b\u043e\u0436\u043a\u0430 \u0434\u0435\u0433\u0434\u044f \u043a\u043e\u0442\u043e\u0440\u0430\u044f \u043c\u043d\u0435 \u043d\u0435 \u0434\u0430\u0432\u0430\u043b\u0430 \u043d\u043e\u0440\u043c\u0430\u043b\u044c\u043d\u043e \u0432\u044b\u0441\u043f\u0430\u0442\u044c\u0441\u044f \ud83d\ude42<br \/>   \u042d\u0442\u043e \u0442\u043e\u0442\u0430\u043b\u044c\u043d\u043e\u0435 \u043e\u0442\u0441\u0443\u0442\u0441\u0442\u0432\u0438\u0435 \u043f\u043e\u0434\u0434\u0435\u0440\u0436\u043a\u0438 OUTER JOIN. \u041d\u043e \u043a\u0430\u043a \u043e\u043a\u0430\u0437\u0430\u043b\u043e\u0441\u044c \u0434\u0435\u0433\u043e\u0442\u044c \u0441 \u043b\u0435\u0433\u043a\u043e\u0441\u0442\u044c\u044e \u043f\u0440\u0435\u0432\u0440\u0430\u0449\u0430\u0435\u0442\u0441\u044f\u2026 \u043f\u0440\u0435\u0432\u0440\u0430\u0449\u0430\u0435\u0442\u0441\u044f\u2026 \u043f\u0440\u0435\u0432\u0440\u0430\u0449\u0430\u0435\u0442\u0441\u044f\u2026   <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[],"tags":[],"class_list":["post-304643","post","type-post","status-publish","format-standard","hentry"],"_links":{"self":[{"href":"https:\/\/savepearlharbor.com\/index.php?rest_route=\/wp\/v2\/posts\/304643","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/savepearlharbor.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/savepearlharbor.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/savepearlharbor.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/savepearlharbor.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=304643"}],"version-history":[{"count":0,"href":"https:\/\/savepearlharbor.com\/index.php?rest_route=\/wp\/v2\/posts\/304643\/revisions"}],"wp:attachment":[{"href":"https:\/\/savepearlharbor.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=304643"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/savepearlharbor.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=304643"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/savepearlharbor.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=304643"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}