I am trying to write a query on a table that contains null values. I do not want to show the column for the field if the record is null. How do I control this?

I don't think you can supress the column based on a condition, but you can easily supress the record/row. In the criteria field for the column you want to filter, just add 'Is Not Null' (excluding quotes). The query will return all of the records in the table where the column you are filtering has a value...