title: Query to replace a comma in SQL?
body: <p>I have a table with the columns employee, address, city, state and zipcode. I have merged address, city, state, zipcode to a single column 'address' separating each field by comma. </p>
  
  <p>My issue is, if one of the fields is null, an extra comma will be inserted. For example if <code>city</code> is null the resulting value will be like <code>address,,state,zipcode</code>. I need to remove this extra comma. How to do this? Please help.</p>