Functions

Syntax#

CREATE [OR REPLACE] FUNCTION function_name [ (parameter [,parameter]) ]

RETURN return_datatype

IS | AS

[declaration_section]

BEGIN executable_section

[EXCEPTION exception_section]

END [function_name];

Generate GUID

Create Or Replace Function Generateguid
Return Char Is
    V_Guid Char(40);
Begin
    Select Substr(Sys_Guid(),1,8)||'-'||Substr(Sys_Guid(),9,4)||'-'
                        ||Substr(Sys_Guid(),13,4)||'-'||Substr(Sys_Guid(),17,4)||'-'
                        ||Substr(Sys_Guid(),21) Into V_Guid 
                        From Dual;
    Return V_Guid;
Exception
    When Others Then
    dbms_output.put_line('Error '|| SQLERRM);
End Generateguid;

Calling Functions

There are a few ways to use functions.

Calling a function with an assignment statement

DECLARE
    x NUMBER := functionName(); --functions can be called in declaration section
BEGIN
    x := functionName();
END;

Calling a function in IF statement

IF functionName() = 100 THEN
    Null;
END IF;

Calling a function in a SELECT statement

SELECT functionName() FROM DUAL;