title: How can I get this query to return 0 instead of null?
body: <p>I have this query:</p>
  
  <pre><code>SELECT (SUM(tblTransaction.AmountPaid) - SUM(tblTransaction.AmountCharged)) AS TenantBalance, tblTransaction.TenantID
      FROM tblTransaction
      GROUP BY tblTransaction.TenantID
  </code></pre>
  
  <p>But there's a problem with it; there are other TenantID's that don't have transactions and I want to get those too.</p>
  
  <p>For example, the transaction table has 3 rows for bob, 2 row for john and none for jane. I want it to return the sum for bob and john AND return 0 for jane. (or possibly null if there's no other way)</p>
  
  <p>How can I do this?</p>
  
  <p>Tables are like this:</p>
  
  <pre>
  Tenants  
    ID  
    Other Data  
  Transactions  
    ID  
    TenantID (fk to Tenants)
    Other Data  
  </pre>