Count number of records returned by temp table - SQL Server
<p>My script is as below</p>

<pre><code>CREATE TABLE #t (Id int, Name varchar(10))
INSERT INTO #t VALUES (1, 'A')
INSERT INTO #t VALUES (1, 'B')
INSERT INTO #t VALUES (1, 'C')
INSERT INTO #t VALUES (1, 'D')
INSERT INTO #t VALUES (2, 'E')

SELECT COUNT(0)FROM (SELECT COUNT(0) FROM #t GROUP BY Id) a
</code></pre>

<p>but I am getting an error</p>

<blockquote>
  <p>Msg 8155, Level 16, State 2, Line 5
  No column name was specified for column 1 of 'A'.</p>
</blockquote>