title: SQL - Only one expression can be specified in the select list when the subquery is not introduced with EXISTS
body: <p>I am trying to set a variable to the return value of a select statement by doing: </p>
  
  <pre><code>declare @Owner int = 0;
  
  set @Owner = (select distinct [TodoTitle].[owner], TodoTitle.id 
                from TodoTitle
                join todoTree on TodoTitle.id = todoTree.todoid
                where todoid = @todoId);
  </code></pre>
  
  <p>I keep getting this error:</p>
  
  <blockquote>
    <p>Only one expression can be specified in the select list when the subquery is not introduced with EXISTS.</p>
  </blockquote>
  
  <p>Any help would be appreciated,</p>
  
  <p>Mark</p>