Databases Reference
In-Depth Information
3
Chapter
Oracle Database Functions
In This Chapter
Miscellaneous query operators and
rules
◆
Built-in, single-row functions
◆
Every DBA needs to know about built-in functions. Many of the day-to-
day tasks of a DBA involve queries, and these queries often need to trans-
form or summarize information in database tables and views. Many
DBAs will also create and maintain a library of customized functions
(also known as user-defined functions) for business areas in the company
and help to deploy these user-defined functions.
This chapter covers the built-in functions and provides an introduc-
tion to user-defined functions. However, before we dig into the functions
themselves, we'll talk about some of the general rules for building que-
ries, including how the
Customized (user-defined) functions
◆
DUAL
table is used, how
NULL
values work, and
how numbers and strings are constructed.
