Database Reference
In-Depth Information
Example 22:
Example 18 is repeated here using ANSI syntax (show all program-
name and course-name combinations).
Example 23:
Example 21 is repeated here using ANSI syntax (student-name and
hall-name combinations, including students not assigned to halls):
12.8 Queries Involving the use of Functions
SQL allows the use of several functions in order to provide the user (programmer)
with flexibility in specifying queries. We will briefly discuss the following categories of
SQL functions:
•
Row functions
•
Date functions
•
Data conversion functions
•
Aggregation (group) functions
•
Programmer defined functions
12.8.1 Row Functions
Row functions are functions that act on rows (tuples) of a query result, typically affecting
the value of specific columns of a given row. Figure
12-7
provides a list of commonly
row functions that can be used within a query specification. The list is by no means
exhaustive.
