Using Functions to Customize Reports

A SQL function is a program that performs an operation on data. SQL functions provide a powerful way to perform operations when retrieving data from a table. For example, you may need to display employee names in uppercase in a report. Or you may need to display employees' hire dates with the name of the month spelled out.

Many functions work on specific data types. Each value manipulated by Oracle XE has a data type. Data types provide a way to define the behavior of data. When you create a table, you must specify a data type for each of its columns.

The three main types of data that functions work on are:

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Character
*
Number
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Date