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    copied!<p>In Lambda :</p> <pre><code> var persons = Persons.Where(p=&gt;(p.PersonLocations.Select(ps=&gt;ps.Location) .Where(l=&gt;l.Description == "Amsterdam").Count() &gt; 0) &amp;&amp; (p.PersonRoles.Select(pr=&gt;pr.Role) .Where(r=&gt;r.Description == "Student").Count() &gt; 0)); </code></pre> <p><strong>query result:</strong></p> <pre><code>SELECT [t0].[personId] AS [PersonId], [t0].[description] AS [Description] FROM [Persons] AS [t0] WHERE ((( SELECT COUNT(*) FROM [personlocations] AS [t1] INNER JOIN [Locations] AS [t2] ON [t2].[locationid] = [t1].[locationid] WHERE ([t2].[description] = @p0) AND ([t1].[personid] = [t0].[personId]) )) &gt; @p1) AND ((( SELECT COUNT(*) FROM [PersonRoles] AS [t3] INNER JOIN [Roles] AS [t4] ON [t4].[roleid] = [t3].[roleid] WHERE ([t4].[description] = @p2) AND ([t3].[personid] = [t0].[personId]) )) &gt; @p3) </code></pre> <p><strong>Using Contains():</strong></p> <pre><code>var persons = Persons .Where(p=&gt;(p.Personlocations.Select(ps=&gt;ps.Location) .Select(l=&gt;l.Description).Contains("Amsterdam")) &amp;&amp; (p.PersonRoles.Select(pr=&gt;pr.Role) .Select(r=&gt;r.Description).Contains("Student"))); </code></pre> <p><strong>query result:</strong></p> <pre><code>SELECT [t0].[personId] AS [PersonId], [t0].[description] AS [Description] FROM [Persons] AS [t0] WHERE (EXISTS( SELECT NULL AS [EMPTY] FROM [personlocations] AS [t1] INNER JOIN [Locations] AS [t2] ON [t2].[locationid] = [t1].[locationid] WHERE ([t2].[description] = @p0) AND ([t1].[personid] = [t0].[personId]) )) AND (EXISTS( SELECT NULL AS [EMPTY] FROM [PersonRoles] AS [t3] INNER JOIN [Roles] AS [t4] ON [t4].[roleid] = [t3].[roleid] WHERE ([t4].[description] = @p1) AND ([t3].[personid] = [t0].[personId]) )) </code></pre> <p><strong>using join():</strong></p> <pre><code>var persons = Persons .Join(Personlocations, p=&gt;p.PersonId, ps=&gt;ps.Personid, (p,ps) =&gt; new {p,ps}) .Where(a =&gt; a.ps.Location.Description =="Amsterdam") .Join(PersonRoles, pr=&gt; pr.p.PersonId, r=&gt;r.Personid,(pr,r) =&gt; new {pr.p,r}) .Where(a=&gt;a.r.Role.Description=="Student") .Select(p=&gt; new {p.p}); </code></pre> <p>Query Result:</p> <pre><code>SELECT [t0].[personId] AS [PersonId], [t0].[description] AS [Description] FROM [Persons] AS [t0] INNER JOIN [personlocations] AS [t1] ON [t0].[personId] = [t1].[personid] INNER JOIN [Locations] AS [t2] ON [t2].[locationid] = [t1].[locationid] INNER JOIN [PersonRoles] AS [t3] ON [t0].[personId] = [t3].[personid] INNER JOIN [Roles] AS [t4] ON [t4].[roleid] = [t3].[roleid] WHERE ([t4].[description] = @p0) AND ([t2].[description] = @p1) </code></pre> <p>You may want test wich one is faster with large data.</p> <p>Good luck.</p> <p>Giuliano Lemes</p>
 

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