title: TSQL Oddity with String_Agg
body: <p>This query returns the wrong results for the second string Agg function:</p>
  
  <pre><code>select
  string_agg(t.name, ';') as BBB,
  string_agg(t.name, ', ' ) as CCC
  from sys.tables as t 
  </code></pre>
  
  <p>But it works if you alter t.name eg:</p>
  
  <pre><code>select
  string_agg(t.name, ';') as BBB,
  string_agg('' + t.name, ', ' ) as CCC
  from sys.tables as t 
  </code></pre>
  
  <p>Any idea why?  Is this a bug?</p>