CHAPTER 3 INTRODUCTION TO REPORTING SERVICES DESIGN WITH SQL SERVER DATA TOOLS
either NULL or Blank. Unlike a NULL value, a Blank value can be an empty string. A NULL value indicates
that the value is unknown, and NULL values can’t be evaluated with non-NULL values. In Chapter 2, you
built logic into the stored procedure to handle NULL parameter values so that when the user doesn’t
supply a value, the query returns all records. If the user selects a specific value, only the records that
match that parameter value are returned. Execute the stored procedure with NULL values, and make sure
you’re getting the results you expect. You can see the results of the stored procedure execution in
Figure 3-10.Figure 3-10. Data returned from the stored procedure Note When you are prompted for the parameter values, Blank is the default value. To have the stored
procedure execute without a data type error, you must select the value of NULL.