MySQL存儲過程+自定義函數 簡單示例

drop table if exists students;
CREATE TABLE `students` (
`stu_id` BIGINT(20) NOT NULL DEFAULT '0' COMMENT '學號',
`stu_name` VARCHAR(50) NULL DEFAULT '' COMMENT '姓名',
`stu_sex` INT(11) NULL DEFAULT '0' COMMENT '性別',
`cla_id` BIGINT(20) NULL DEFAULT '0' COMMENT '班級ID',
`stu_phone` BIGINT(20) NULL DEFAULT '0' COMMENT '手機號',
PRIMARY KEY (`stu_id`)
)
COLLATE='latin1_swedish_ci'
ENGINE=InnoDB;


delimiter //
drop function if exists print //

create function print (str varchar(100)) returns varchar(100)
begin
declare x varchar(100) default '';
set x = str;
return x;
end
/
delimiter ;
select print('hhehehe');


delimiter //
drop function if exists rand_string //

create function rand_string(n int) returns varchar(100)
begin
declare low_str varchar(255) default 'abcdefghijklmnopqrstuvwxyz';
declare up_str varchar(255) default 'ABCDEFGHIJKLMNOPQRSTUVWXYZ';
declare i int default 0;
declare return_str varchar(255) default '';
while i < n do
if i = 0 then
set return_str = concat(return_str, substring(up_str, floor(1 + 26 * rand()), 1));
else
set return_str = concat(return_str, substring(low_str, floor(1 +26 * rand()), 1));
end if;
set i = i + 1;
end while;
return return_str;
end
/
delimiter ;
select rand_string(5);


delimiter //
drop function if exists rand_sex //
create function rand_sex() returns int
begin
declare sex int default 0;
set sex = round(rand());
return sex;
end
/
delimiter ;

select rand_sex();

delimiter //
drop procedure if exists stu_inserts;
create procedure stu_inserts(in n int)
begin
declare stu_id bigint default 10001;
declare stu_name varchar(50) default '';
declare stu_sex int default 1;
declare cla_id bigint default 1;
declare i int default 0;
while i < n do
set stu_name = rand_string(5);
set stu_sex = rand_sex();
if stu_id % 100 = 0 then
set cla_id = cla_id + 1;
end if;
insert into students(stu_id, stu_name, stu_sex, cla_id) values(stu_id, stu_name, stu_sex, cla_id);
set stu_id = stu_id + 1;
end while;
end
/
delimiter ;

call stu_inserts(2000);

set @ss = 'abcdefghijklmnopqrstuvwxyz';
select length(@ss);
select substring(@ss, 28, 1);