Create a function in MySQL

MySQL create function one, to see whether the function of creating a function is turned on:
Mysql> Show variables like '%func% ';
+-----------------------------------------+-------+
| variable_name | Value |
+-----------------------------------------+-------+
| log_bin_trust_function_creators | On |
+-----------------------------------------+-------+
1 row in Set (0.02 sec)
Second, if value is off, you need to turn it on.
mysql> set global Log_bin_trust_function_creators=1; Third, when creating a function, select the database First,
mysql> use XXX;
Database changed
Delimiter $$ is to set $$ as the command termination symbol, in place of the semicolon, because the semicolon is used in begin...end;
Mysql> delimiter $$
CREATE FUNCTION First_func (param1 varchar (5), parmam2 varchar (5), param3 varchar (10))
RETURNS TINYINT
BEGIN
RETURN 1;
END
After the function is created, you need to restore the semicolon to the command termination symbol.
Mysql> delimiter; Four, test:
Mysql> Select First_func (' AAA ', ' BBB ', ' CCC ');
+-------------------------------+
| First_func (' AAA ', ' BBB ', ' CCC ') |
+-------------------------------+
| 1 |
+-------------------------------+
1 row in Set (0.47 sec) v. Delete function:
mysql> drop function First_func;
Query OK, 0 rows affected (0.11 sec) Vi. viewing functions
1) Show function status
Displays basic information about all functions in the database
2) View a specific function

Mysql>show Create function function;

Above: http://blog.csdn.net/tfhui928/article/details/6058074

Example:

--see if the CREATE function function is turned on
SHOW VARIABLES like '%func% ';

--Open the CREATE FUNCTION function and set Variable_name to 1
SET GLOBAL Log_bin_trust_function_creators=1;

--View all functions in the database
SHOW FUNCTION STATUS;

--See the specific function
SHOW CREATE FUNCTION Test_func

--delete function
DROP FUNCTION Test_func

--Create a query function
DELIMITER $$
CREATE FUNCTION Test_func (param1 VARCHAR), param2 int,param3 CHAR (5))
RETURNS INT
BEGIN
DECLARE ret_val int;--Defining variables
SELECT MAX (ID) into ret_val from test;
RETURN Ret_val;

END

--Execution function
SELECT test_func (' var ', ' n ', ' char ');

--Create an assignment function
DELIMITER $$
CREATE FUNCTION test_func1 (param1 int,param2 VARCHAR (20))
RETURNS INT
BEGIN
DECLARE Return_val INT;
DECLARE Val INT DEFAULT 2;
IF Val>1 Then
SET return_val = val;
ELSE
SET return_val = 1;
END IF;
RETURN Return_val;
END

--Execution function
SELECT test_func1 (1, ' admin ');

Transferred from: http://my.oschina.net/u/1273696/blog/181995

Create a function in MySQL