title: SQL Server Execution Plan issue
body: <p>I've got 2 tables</p>
  
  <pre><code>CREATE TABLE [dbo].[T2] (
      [Id] INT            IDENTITY (1, 1) NOT NULL,
      [F1] NVARCHAR (100) NULL,
      [F2] NVARCHAR (100) NULL,
      [F3] NVARCHAR (MAX) NULL,
      PRIMARY KEY CLUSTERED ([Id] ASC)
  );
  
  GO
  CREATE NONCLUSTERED INDEX [IX_T2_F1_F2]
      ON [dbo].[T2]([F1] ASC, [F2] ASC);
  </code></pre>
  
  <p>AND</p>
  
  <pre><code>CREATE TABLE [dbo].[T3] (
      [Id] INT            IDENTITY (1, 1) NOT NULL,
      [F1] NVARCHAR (100) NULL,
      [F2] NVARCHAR (100) NULL,
      [F3] NVARCHAR (MAX) NULL,
      PRIMARY KEY CLUSTERED ([Id] ASC)
  );
  
  GO
  CREATE NONCLUSTERED INDEX [IX_T3_F1_F2]
      ON [dbo].[T3]([F1] ASC, [F2] ASC)
      INCLUDE([F3]);
  </code></pre>
  
  <p>And these are my execution plans</p>
  
  <p><a href="https://i.stack.imgur.com/eOQTr.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/eOQTr.png" alt="enter image description here"></a></p>
  
  <p>The question is why Query #2's execution plan is not <code>Index Seek (NonClustered)</code>, why the Query Optimizer chooses to scan clustered index on PK, instead of non-clustered index <code>{F1,F2}</code> ?</p>
  
  <p>Update #1:</p>
  
  <p><a href="https://i.stack.imgur.com/tbA47.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/tbA47.png" alt="Query #2 Stats"></a></p>