Chapter 4. Data Retrieval

Chapter 3 discussed the various definitions of data objects. These objects were created and defined using the Data Definition Language (DDL). This chapter takes those objects and demonstrates how to retrieve data from them using the Data Manipulation Language (DML) as defined by SQL. This chapter looks at the SQL statement types, SELECT and CALL. The CALL statement is covered at the end of the chapter and can be used to invoke a stored procedure that resides on the server. A stored procedure can return one or more result sets. This chapter primarily covers SELECT and how the resulting data can be grouped and ordered. As the examples progress through the chapter, they will demonstrate more complex methods of data retrieval. What we will not cover here are some of the more advanced DML that DB2 has to offer, such as triggers, recursion, and online analytical processing (OLAP) features. These advanced features are covered in the Certification Guide for Database Administrators.