Summary of PL/SQL Built-In Functions

The function REPLACE returns the value of its first argument if its second argument is null, whether the optional third argument is present or not. For example, the following call to REPLACE does not make any change to the value of OLD_STRING:

DECLARE

string_type VARCHAR2(60);

old_string string_type%TYPE := 'Apples and oranges'; my_string string_type%TYPE := 'more apples';

--NULL is a valid argument to REPLACE, but does not match

--anything so no replacement is done.

new_string string_type%TYPE := REPLACE(old_string, NULL, my_string);

BEGIN

dbms_output.put_line('Old string = ' || old_string); dbms_output.put_line('New string = ' || new_string);

END;

/

If its third argument is null, REPLACE returns its first argument with every occurrence of its second argument removed. For example, the following call to REPLACE removes all the dashes from DASHED_STRING, instead of changing them to another character:

DECLARE

string_type VARCHAR2(60);

dashed string_type%TYPE := 'Gold-i-locks';

--When the substitution text for REPLACE is NULL,

--the text being replaced is deleted.

name string_type%TYPE := REPLACE(dashed, '-', NULL);

If its second and third arguments are null, REPLACE just returns its first argument.

Summary of PL/SQL Built-In Functions

PL/SQL provides many powerful functions to help you manipulate data. These built-in functions fall into the following categories:

error reporting number character

datatype conversion date

object reference miscellaneous

Table 2–3 shows the functions in each category. For descriptions of the error-reporting functions, see Chapter 13. For descriptions of the other functions, see Oracle Database SQL Reference.

Except for the error-reporting functions SQLCODE and SQLERRM, you can use all the functions in SQL statements. Also, except for the object-reference functions DEREF, REF, and VALUE and the miscellaneous functions DECODE, DUMP, and VSIZE, you can use all the functions in procedural statements.

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Summary of PL/SQL Built-In Functions

Although the SQL aggregate functions (such as AVG and COUNT) and the SQL analytic functions (such as CORR and LAG) are not built into PL/SQL, you can use them in SQL statements (but not in procedural statements).

Fundamentals of the PL/SQL Language 2-29

Summary of PL/SQL Built-In Functions

Table 2–3 Built-In Functions

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