title: Microsoft SQL Server - restricting subqueries
body: <p>This is mostly a curiosity question. I've just experienced a situation where on a test database I had the following query:</p>
  
  <pre><code>update table 
  set column1 = 1 
  where column2 in (1,2)
  </code></pre>
  
  <p>But this kept executing with the error that subquery returned more than one value. </p>
  
  <p>Now I checked to make sure I did not have multiple identity keys or that the 'in' values were unique. so for all intents and purposes this should not have happened. </p>
  
  <p>Checking on the LIVE copy of the database, same query did not have an issue. Hence, finally, my question is:</p>
  
  <p>What can you do to the Microsoft SQL Server settings or database structure that would create such a scenario?</p>