title: Expression for Lookup activity result when stored procedure returns scalar value
body: <p>I'm using a Lookup activity that returns an scalar result and I want to use that result to build a dinamic query using a concat expression. However, I'm receiving an error complaining that my SQL query is not well formated. This is how I'm building the query:</p>
  
  <pre><code>@concat('SELECT v.CscadaEventId as EventId, 
  v.EndDate as EndDateUtc 
  FROM v_cscadaevents v 
  INNER JOIN cscadaevents e
  ON e.cscadaeventId = v.CscadaEventId 
  WHERE v.CscadaEventId IN(', activity('LookupUnfinishedAlarms').output.firstRow, ') AND e.EndDate IS NOT NULL;')
  </code></pre>
  
  <p>I expect that to return a query like this:</p>
  
  <pre><code>SELECT v.CscadaEventId as EventId, 
  v.EndDate as EndDateUtc 
  FROM v_cscadaevents v 
  INNER JOIN cscadaevents e
  ON e.cscadaeventId = v.CscadaEventId WHERE v.CscadaEventId IN(2329390,2340616,2342078,2345857,2361240,2362088,2362574,2377062,2378594,2379357) AND e.EndDate IS NOT NULL;
  </code></pre>
  
  <p>I had see some examples where the lookup return multiple columns, and the right expression is <code>activity('LookupUnfinishedAlarms').output.firstRow.myColumnName</code> but what about when the lookup activity return an scalar value, as in  my case?</p>
  
  <p>This is the full error so far:</p>
  
  <blockquote>
    <p>You have an error in your SQL syntax; check the manual that
    corresponds to your MariaDB server version for the right syntax to use
    near
    &apos;\"output\":\"2329390&#44;2340616&#44;2342078&#44;2345857&#44;2361240&#44;2362088&#44;2362574&#44;2377062&#44;237859&apos;
    at line
    6,Source=Microsoft.DataTransfer.Runtime.GenericOdbcConnectors,''Type=System.Data.Odbc.OdbcException,Message=ERROR
    [42000] [Microsoft][MariaDB] You have an error in your SQL syntax;
    check the manual that corresponds to your MariaDB server version for
    the right syntax to use near
    &apos;\"output\":\"2329390&#44;2340616&#44;2342078&#44;2345857&#44;2361240&#44;2362088&#44;2362574&#44;2377062&#44;237859&apos;
    at line 6,Source=MariaDBODBC_sb64.dll</p>
  </blockquote>