Grid display data is null

I use SqlServer database is, is to use Java and JSP development CRM system,
The java code is as follows:
c.event.attach(new LeadsBehavior());
c.render_sql(sql,“CRMLeadsID”, “LeadsName,Company,Phone”);
but,When data display the page,There will also be null appear.So I can’t leave null display to the user,What better this law can solve.

You can

a) user render_sql instead of render table, and add some rules to SQL, which will ignore records with NULL values


b) you can redefine beforeRender in the custom behavior, and add some logic, which will check is field == NULL and set it to the some default value.