Oracle Tips by Burleson

Calling PL/SQL Functions from SQL*Plus

To call a function in SQL*Plus, simply embed it in a SQL statement.  Below we execute the f2c function by selecting it from the pseudo table called dual.  The “Dual” pseudo-table allows you to select from it to execute functions.

SQL> select f2c(40) from dual; 

   F2C(40)
----------
4.44444444 

The function can be applied to any select statement that passed the correct datatype.

SQL> select f2c(quantity) from sales; 

F2C(QUANTITY)
-------------
   537.777778
   -12.222222
   93.3333333
   204.444444
   426.666667
   82.2222222
   482.222222
…
   37.7777778
   4426.66667
   3037.77778
   4926.66667
   4871.11111
   37.7777778 

100 rows selected.

The above example calculates the degrees Celsius from all the quantity values in the sales table (pretending that they are actually degrees Fahrenheit).   For each row, the f2c function was executed, passing in the value of quantity for that row and returning that value converted to degrees Celsius. 

Below is an example of a function that takes an author’s first and last name and returns a formatted complete name.  Notice that it used the %type definition for the passed in the variables. 

SQL> create or replace function full_name
  2    (v_fname IN author.author_first_name%type,
  3     v_lname IN author.author_last_name%type)
  4    return varchar2
  5  as
  6  begin
  7    return initcap(v_fname||' '||v_lname);
  8  end;
  9  /
 

Function created.

SQL> select
  2    full_name(author_first_name, author_last_name) from author; 

FULL_NAME(AUTHOR_FIRST_NAME,AUTHOR_LAST_NAME)
----------------------------------------------------
Mark Jones
Alvis Hester
Erin Weaton
Pierre Jeckle
Lester Withers
Juan Petty
Louis Clark
Minnie Mee
Dirk Shagger
Diego Smith

The above book excerpt is from:

Easy Oracle PL/SQL Programming

Get Started Fast with Working PL/SQL Code Examples

ISBN 0-9759135-7-3   

John Garmany 

http://www.rampant-books.com/book_2005_1_easy_plsql.htm