how to create function in mysql-Mysql Tutorial-php.cn

In mysql, you can create a function through the syntax "CREATE FUNCTION func_name ([func_parameter])", where "CREATE FUNCTION" is the keyword used to create a function.

how to create function in mysql

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Creating a function in a MySQL database

Syntax

CREATE FUNCTION func_name ( [func_parameter] ) //括号是必须的，参数是可选的 RETURNS type [ characteristic ...] routine_body

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CREATE FUNCTION keyword used to create a function;

func_name represents the name of the function;

func_parameters is the parameter list of the function , the parameter list is in the form: [IN|OUT|INOUT] param_name type

IN: indicates input parameters;

OUT: indicates output parameters;

INOUT: indicates both It can be input or output;

param_name: indicates the name of the parameter;

type: indicates the type of the parameter, which can be any type in the MySQL database;

RETURNS type: The statement indicates the type of data returned by the function;

characteristic: specifies the characteristics of the stored function, and the value is the same as that of the stored procedure. For details, please visit - MySQL stored procedure usage;

Example

Create sample database, sample table and insert sample data script:

create database hr; use hr; create table employees ( employee_id int(11) primary key not null auto_increment, employee_name varchar(50) not null, employee_sex varchar(10) default '男', hire_date datetime not null default current_timestamp, employee_mgr int(11), employee_salary float default 3000, department_id int(11) ); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('David Tian','男',10,7500,1); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Black Xie','男',10,6600,1); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Moses Wang','男',10,4300,1); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Rena Ruan','女',10,5300,1); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Sunshine Ma','女',10,6500,2); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Scott Gao','男',10,9500,2); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Warren Si','男',10,7800,2); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Kaishen Yang','男',10,9500,3); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Simon Song','男',10,5500,3); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Brown Guan','男',10,5000,3); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Eleven Chen','女',10,3500,2); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Cherry Zhou','女',10,5500,4); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Klause He','男',10,4500,5); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Maven Ma','男',10,4500,6); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Stephani Wang','女',10,5500,7); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Jerry Guo','男',10,8500,1); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Gerardo Garza','男',10,25000,8); insert into employees(employee_name,employee_sex,employee_mgr,employee_salary,department_id) values ('Derek Wu','男',10,5500,5); select * from employees;

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Create function-get employee name and employee salary based on ID

DELIMITER // CREATE FUNCTION GetEmployeeInformationByID(id INT) RETURNS VARCHAR(300) BEGIN RETURN(SELECT CONCAT('employee name:',employee_name,'---','salary: ',employee_salary) FROM employees WHERE employee_id=id); END// DELIMITER ;

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Call function

In MySQL - functions are used in the same way as MySQL internal functions.

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